"In this alternate timeline, Zeratul has survived to see the battle against Amon fully unfold. As a commander, he harnesses the power of the xel'naga for his army and upgrades."
Zeratul is a commander for the Co-op Missions mode. He brings the power of xel'naga-enhanced protoss to bear against his enemies, and can utilize xel'naga relics to turn the tide in his favor. He is the mode's second hybrid-type commander, combining elements of the protoss and xel'naga arsenal.
Zeratul is deployed to the battlefield as a hero and can build advanced protoss forces augmented with xel'naga technology. Scattered through the map are a series of random artifact fragments Zeratul must collect. Using prophetic vision will give Zeratul a hint as to its location, and once found it will give Zeratul's forces new upgrades and top bar abilities.
Zeratul's top bar abilities are customizable, and each tier has options to select from. Zeratul can call down Legendary legions to help him in battle, which cannot be directly controlled but directed to locations. Zeratul can also utilize these customizable top bar to augment his army with passive abilities or new calldowns. Upon gaining all three artifact fragments, Zeratul can call down one of two xel'naga constructs, the Avatar of Form or the Avatar of Essence.[1]
"Alas, the day has finally come. The End War is upon us... and all of creation depends on our victory. I must look again to the wisdom of the Xel'Naga... their ancient constructs hold the power that could be our salvation!"
Artifact Fragment Spawn Rate: -2 sec – -60 sec (down to a minimum of 120 sec)
Support Calldown Cooldown Reduction: -1% – -30%
Power Set 3
Legendary Legion Cost: -1% – -30% (down to a minimum of 560 )
Avatar Cooldown: -4 sec – -120 sec
Prestiges[]
Level 1 – Anakh Su'n
Advantage: Zeratul can deploy the Void Seeker, granting all friendly units in a target area Super Cloak for 15 seconds.
Disadvantage: The Void Seeker can no longer transport Zeratul.
Level 2 – Knowledge Seeker
Advantage: Zeratul can collect an unlimited number of Artifact Fragments.
Disadvantage: Zeratul's combat units cost 25% more.
Zeratul can find the third and subsequent Xel'Naga Artifact Fragments without Level 2 (Prophecy Fulfilled), however he will not be able to select an Avatar without said talent.
Zeratul can find a maximum of 103 Artifact Fragments in this prestige.
Zeratul's level 15 talent (Purity of Will) will also scale from the bonus Artifact Fragments with this prestige, but gain max effect after collect 100 fragments.
Level 3 – Herald of the Void
Advantage: Each collected Artifact Fragment reduces the cooldown of Zeratul's Shadow Cleave by 5 seconds. Shadow Cleave spawns a tornado that damages and slows enemy units.
Disadvantage: Zeratul can only collect up to two Artifact Fragments.
Without the upgrades granted from the third Artifact Fragment, Zeratul's forces lose a significant portion of their survivability, due to certain abilities and passives being disabled.
Game Unit[]
Zeratul deploys personally to the battlefield to aid his army. He serves as a viable source of air and ground damage, dealing 100 damage per attack. Zeratul himself can hunt around the map for artifact fragments, and use Prophetic Vision to close in on their location. While Zeratul himself is relatively fragile, his high mobility with blink and Void Seeker can let him move in and out of combat and strike key targets.
Abilities[]
One With the Shadows
Zeratul is permanently cloaked. He becomes immune to damage for 0.5 seconds after being attacked. Cannot occur more than once every 5 seconds.
Deals 100 damage to nearby enemies. Hits both ground and air.
Purity of Will: Increases the Shadow Cleave damage by 10 per artifact fragment.
Herald of the Void: Reduces the Shadow Cleave cooldown by 5 seconds per artifact fragment. Shadow Cleave spawns a tornado which attacks enemy units, dealing 20 damage per second and slowing them by 30% within a radius of 1.5. Lasts for 5 seconds. Detectors are targeted in priority.
Usage
Hotkey
E
Duration
5 (with Herald of the Void)
Cooldown
12
7 (with Herald of the Void and first artifact fragment)
2 (with Herald of the Void and second artifact fragment)
Zeratul will gain additional shields (+50), increased Shadow Cleave damage (+10), and additional charges of Blink (+1) for each Artifact Fragment he finds.
Zeratul can customize his calldown abilities from a variety of options. His Legendary Legion calldowns are gained at the start of a match, but his other three top bar abilities are obtained for each artifact fragment collected. Once a top bar ability is chosen, it is finalized for that mission.
First Tier
The following abilities are available to select at the start of the game, and focus on Zeratul's summonable Legendary legions. Once a legion is selected, it cannot be changed.
Telbrus Legion
Call down Telbrus and his legendary legion of Zealots to aid in the battle. This legion cannot be directly controlled but can be guided via the top-bar and will fight for 60 seconds.
Usage
Cost
800 Mastery: -8 per Legendary Legion Cost mastery point. Down to a minimum 560
Call down Zoraya and her legendary legion of Void Rays to aid in the battle. This legion cannot be directly controlled but can be guided via the top-bar and will fight for 60 seconds.
Usage
Cost
800 Mastery: -8 per Legendary Legion Cost mastery point. Down to a minimum 560
Call down Serdath and his legendary legion of Dark Archons to aid in the battle. This legion cannot be directly controlled but can be guided via the top-bar and will fight for 60 seconds.
Usage
Cost
800 Mastery: -8 per Legendary Legion Cost mastery point. Down to a minimum 560
The following abilities are available to pick from upon discovering the first artifact fragment.
Stasis Beam
Fires a beam emanating from the Artifact Holder that places enemies in stasis for 15 seconds. Units in stasis cannot move, attack, be attacked, or be affected by abilities.
Usage
Duration
15
Cooldown
90 Mastery: -0.9 per Support Calldown Cooldown Reduction mastery point. Down to a minimum 63
Campaign Acquisition
Unlock
Initially available.
Acquisition
Notes
Once Stasis Beam is chosen as the support calldown from the top bar, it must be kept until the end of the mission.
Deploys a tesseract monolith at the target location. Tesseract monoliths can stun enemies, project themselves, and protect themselves from damage. Stores up to 3 charges. (Starting with 1 charge)
Usage
Cooldown
180 Mastery: -1.8 per Support Calldown Cooldown Reduction mastery point. Down to a minimum 126
Campaign Acquisition
Unlock
Reach Zeratul Level 5.
Acquisition
Notes
Once Deploy Tesseract Monolith is chosen as the support calldown from the top bar, it must be kept until the end of the mission.
Summons an invulnerable Void Suppression Crystal that slows the movement and attack speeds of enemy units by 70% and disables enemy structures. The Void Suppression Crystal is controllable and lasts for 30 seconds.
Usage
Duration
30
Cooldown
180 Mastery: -1.8 per Support Calldown Cooldown Reduction mastery point. Down to a minimum 126
Campaign Acquisition
Unlock
Reach Zeratul Level 7.
Acquisition
Notes
Once Void Suppression Crystal is chosen as the support calldown from the top bar, it must be kept until the end of the mission.
The following abilities are available to pick from upon discovering the third artifact fragment, and grant Zeratul his ultimate Avatar calldowns.
Avatar of Form
Call down the Avatar of Form, the embodiment of psionic potential, at the target location. The Avatar of Form is controllable and will fight for 60 seconds.
Herald of the Void: Avatar of Form is unavailable.
Call down the Avatar of Essence, the embodiment of evolutionary potential, at the target location. The Avatar of Essence is controllable and will fight for 60 seconds.
Herald of the Void: Avatar of Essence is unavailable.
Deadly warrior-assassin. Cloak renders the unit invisible without detection. Can teleport to a nearby location and deal damage to enemies along the way.
Assault strider. Can use Barrier to absorb damage and knock back enemy air units.
Can attack ground and air units.
750 300 4
55 (28 with Chronometry)
Life: 400 / Shields: 200 / Armor: 1
MS: 2.25
Annihilation Cannon
Targets: Air
Damage: 40 (+60 vs Armored)
AS: 2.18 / Range 11
Upgrade: +4 (+6 vs Armored) per level
DPS: 18:35 (+1.83)
45.87 (+4.59) vs Armored
Phase Disruptors
Targets: Ground
Damage: 20 (+30 vs Armored)
AS: 1.45 / Range: 5
Upgrade: +2 (+3 vs Armored) per level
DPS: 13.79 (+1.38)
34.48 (+3.45) vs Armored)
Zeratul acquires the following talents as he levels up.
Power of the Xel'Naga
Zeratul has a 100 starting supply and his units have increased life and damage. Buildings do not require pylon power and units cannot be warped directly onto the battlefield. Zeratul's ancient nexus can automatically construct ancient assimilators.
Unlocks the option to select the following Artifact abilities:
Call down Serdath and his legendary legion of dark archons to aid in the battle. Serdath cannot be directly controlled but can be guided via the top-bar.
Summons an invulnerable void suppression crystal that slows the movement and attack speeds of enemy units and disables enemy structures in its vicinity.
Reduces the cooldown of Blink abilities for Zeratul and his units by 50%.
Legendary Legions gain new abilities once the third Artifact Fragment is found:
Telbrus gains the Feedback ability, which drains energy from an enemy unit. Telbrus Zealot Legion gains the Charge ability, which allows them to intercept enemy ground units.
Zoraya and her Void Ray Legion gain the Prismatic Range ability, which increases the range of their weapons as they continue to attack.
Unlocks the following Constructs-level Artifact upgrades after the third Artifact Fragment is found:
Increases the damage absorbed by the xel'naga enforcer's Barrier by 300%. The xel'naga enforcer's Barrier will fully restore its health whenever it activates.
When a xel'naga abrogator's Purification Nova explodes, it generates three smaller Novas that deal 50 damage each to enemy units in their paths.
Units near a xel'naga void arrays in Wormhole Mode have an increased shield regeneration rate of 2 per second.
The Avatar of Form gains the ability to summon Charged Constructs that can individually cast miniature Psionic Storms. The Avatar of Essence gains the ability to transform all enemy units in a large area into a lower evolutionary form.
Zeratul will gain additional shields (+50), increased Shadow Cleave damage (+10), and additional charges of Blink (+1) for each Artifact Fragment he finds.
Either mastery can work out well, depending on the playstyle used. Zeratul's attack speed can greatly increase his early game presence and allow him to be a formidable unit the later game, but a larger army benefits more from an attack speed boost than Zeratul alone does.
Power Set 2
☀Artifact Fragment Spawn Rate :-2 sec – -60 sec
The support calldown cooldown reduction, while powerful, ultimately does not have a large impact on Zeratul's gameplay compared to the artifact fragment spawn rate, which allows him to achieve maximum power faster and overall improves his gameplay. This mastery also directly buffs power set 3 by increasing legion power and allows you to get more out of the legions, or unlocks the avatar earlier to make use of the cooldown mastery.
With his upgrades available much faster to him comparing to other commanders, Zeratul can easily steamroll the enemy much earlier in the game before any significant resistance can be made.
Power Set 3
☀Legendary Legion Cost: -1% – -30% (down to a minimum of 560 )
Or
Avatar Cooldown
-4 sec – 120 sec
Reducing the cost of the Legendary Legion enables Zeratul to make much more avid use of this calldown. This enable Zeratul to summon a highly effective and expendable force to serve as a shield for his expensive army and lead pushes through enemy bases.
On the other hand, avatar cooldown increases avatar uptime, allowing the player to deal more damage with the Avatar of Form or to have higher buff coverage with the Avatar of Essence. This mastery is preferred when the player cannot or prefer not to use legendary legions.
Prestige Strategies[]
Anakh Su'n allows Zeratul to deploy the Void Seeker as a powerful defensive support ability. Units in a large area of effect gain "super cloak", which means they cannot be detected at all; while they are still vulnerable to attacks and damaging abilities, it is unlikely the enemy will use such things since they cannot see the cloaked army and will behave as though they were not there. Used properly, this prestige can be a great benefit for both armies and allow them to easily win fights that may otherwise prove extremely challenging. The prestige is best used when paired with commanders that have large armies and/or high burst damage potential, to maximize the benefits of the Void Seeker while it is active. Its cooldown is not very long, allowing it to be available for most engagements. A major downside is that without the Void Seeker, Zeratul cannot move about the map freely and will have a harder time retrieving artifact fragments, especially on large maps where the fragments can spawn deep into enemy territory. The Void Seeker's super cloak can be used to retrieve such fragments more safely, but will not be a viable solution in every scenario. Since the artifact fragments spawn at random every mission, the loss of the Void Seeker may be a minor inconvenience, or severely limit Zeratul's capabilities for longer periods of time.
Knowledge Seeker makes Zeratul's army much more expensive. This hinders his offensive potential in the early game since the player will have few units and few spare resources to call in a legendary legion, so they must make good use of Zeratul himself, and once his army begins to grow he must take care to avoid losses and engaging enemies he cannot win against. In return, Zeratul's army can be exponentially more powerful in the late-game - he will gain massive amounts of shields, his army will have very high attack power, and both can be very tanky with armor and shield upgrades. As Zeratul continues to find more and more artifact fragments, he will slowly but surely become an nigh-unstoppable force, both his army and Zeratul himself. However, it will take time to get there, so on maps where the player does not expect the game to last very long, and especially on missions with a finite time limit, this prestige is worthless and a pure hindrance. But if the mission is expected to take a longer period of time, the prestige is very potent, and at the half-hour mark Zeratul can potentially have a dozen fragments and the boost will be very apparent. His mastery to reduce the cooldown of artifact fragments spawning is of utmost importance when using this prestige and has a cascading effect on Zeratul's army growing stronger faster. Zeratul's increased combat unit cost means he will be unlikely to have resources to spawn to call in his legendary legion, which can hurt his presence in the early-game, but eventually his army's increased power will outstrip the legion anyway.
Herald of the Void focuses Zeratul's playstyle on using Zeratul himself instead of building an army. Without the third artifact fragment, his army and calldowns will be bereft of their highest upgrades, limiting their potential going into the late-game and requiring more cautious use of them since his ambushers cannot continuously Blink, his enforcers cannot absorb as much damage with their Barrier, etc. The benefit of this prestige is that Zeratul himself becomes much more powerful offensively. With both fragments, Shadow Cleave's cooldown is reduced to only two seconds and the tornado it spawns will improve its damage, letting Zeratul single-handedly decimate groups of enemies. However, Zeratul himself is still fragile if overwhelmed, and he slightly lower shields without the final artifact fragment. When attack waves spawn, intercepting the enemy and kiting them with Shadow Cleave is preferable to a frontal assault if possible. Against weaker enemies that Zeratul can burst down with Shadow Cleave, he excels; against stronger enemies that will take multiple hits to kill, he is at risk. If facing such unit compositions, Zeratul will still need an army to support him and he should be used alongside them to soften up the enemy before his army engages, and his burst damage and slowing effect help make up for the loss of his army's defensive passives. However, if the enemy consists primarily of weaker, low-HP units, Zeratul will need less support and can even carry the day himself. Either way, the player must micromanage Zeratul well to make the most of his increased damage potential.
Playstyle[]
Zeratul's gameplay will revolve heavily around the Prophetic Vision ability, which allows the player to discover three Xel’Naga Artifact Fragments on the map. Players are encouraged to seek out these Artifact Fragments as they will improve Zeratul in a variety of ways:
Zeratul, his units, calldowns, defensive structures, and even Probes will gain weapon, armor, and shield upgrades with each Artifact Fragment.
Zeratul has no traditional researchable abilities. Instead, Artifact Fragments he finds will grant his units Artifact Enhancements, which are either new abilities or improvements to existing abilities.
Zeratul has a potential of four top-bar abilities, but only one is unlocked at the start of the game. Players unlock new top-bar abilities with each Artifact Fragment they find.
The Legendary Legion calldowns improve with each Artifact Fragment found.
Zeratul himself gains bonuses.
In addition, uniquely among Commanders, Zeratul's top-bar is fully customizable. Both at the start of the game and with each Artifact Fragment recovered, players will be able to choose one additional top-bar ability from a selection of two or three. Players should select these abilities carefully based on both their individual playstyles and the needs of the mission.
I Shall Find A Way[]
Zeratul's unique mechanics make him somewhat tricky to use. While the nature of the artifact pieces means that the player can get a tremendous amount of value for free, it also presents a difficulty: artifacts can be hard to find or be placed right in the middle of an enemy base. Good map awareness and good reflexes are key. Players should familiarize themselves with Zeratul's blink and his ability to use the Void Seeker to traverse great distances, while also being wary of unwittingly dropping Zeratul into a death trap with the Void Seeker.
Protect the Dark Prelate[]
Just as keeping a good eye on Zeratul when he is searching for artifacts is critical, so is keeping him alive during battle. Zeratul himself is a powerful hero, but he has less aggressive abilities then heroes like Fenix or Alarak. His cleave allows him incredible wave clear, but hybrid units and siege units can rapidly wear down Zeratul. This can be especially problematic if he dies directly before the next artifact is ready to be found. Essentially, the player can accidentally increase the time it takes to find the artifacts by poor micro. Xel'Naga Shieldguards can help alleviate this weakness, but players should still keep a careful eye on Zeratul during engagements.
Retribution Will be Swift[]
The army Zeratul can field is almost entirely ground-based, bar the Xel'Naga Watchers, and they are fairly slow-moving. Players should familiarize themselves with the Void Array, which allows Zeratul and his army to traverse the battlefield at incredible speeds. Without them, the player is left watching Zeratul's army perform a slow march across the battlefield while the other commander handles speedier threats. This weakness can be somewhat compensated for by an awareness of map objectives and careful timing, however that strategy will leave Zeratul in a precarious position in the more random mutators.
The Might of the Ancients[]
Zeratul's units function similarly to Nova's army: they are all much more powerful than regular units, but are also much more expensive and limited by a 100 max supply cap. Thus, knowing which units to pick is essential. All of Zeratul's Xel'Naga enhanced units function similarly to the standard variety of the unit at first glance, but they have powerful buffs and additional abilities. The Xel'Naga Enforcer, unlike the Immortal, can target air units with a slower but powerful attack. In a similar vein, the Xel'Naga Abrogator automatically targets enemy units, as opposed to its multiplayer counterpart. As a general rule of thumb, the Xel'Naga Ambusher will form the backbone of Zeratul's forces, due to it effectively replacing zealots as the first combat unit Zeratul gains access to, and Xel'Naga Shieldguards will keep Zeratul's expensive units alive to fight.
Zeratul's Void Templar are capable units. Their blink has the passive ability to do damage to enemy units, allowing Zeratul and his cloaked allies to blink into the middle of an enemy force and shred ground enemies. However, this can be very risky. The player should wait until Zeratul has all three artifact fragments before investing in Void Templar, as their high cost makes them devastating to lose. With the third fragment, the Void Templar gain the ability to fully heal upon taking critical damage, and Zeratul himself becomes a more able combatant with his final upgrades, making a blink into the enemy force a less risky gamble.
Legendary Power[]
Arguably, Zeratul has the most versatile and powerful set of call downs in the game. He can customize his call downs depending on the map and the composition of the enemy forces or the needs of the other commander. Players should practice with all of Zeratul's powerful abilities and examine the different combinations or uses of the units for maximum effect. For example, Serdath's forces can form a powerful wave of crowd control, but they lack the speed of the Telbrus zealots. Similarly, Zeratul's final call downs, the Avatar of Form and the Avatar of Essence, each have different strengths that make them incredibly effective in the proper situations.
Players should experiment with Tesseract Monlyths and Void Suppression Crystals, as both lend powerful effects: the Monlyths give crowd control via stun and the Void Suppression Crystals drastically weaken enemies.
In is important for players to remember that the Legendary Legion is expendable and on a timer. Likewise, the Avatars are powerful, but they can rapidly be crushed by hybrid if the Avatar is left to fend for itself.
In the Defense of Aiur[]
An intriguing ability that Zeratul has access to is the ability to temporarily create a copy of his Tesseract Cannons. With these copies, Zeratul can add some additional firepower to the battlefield or close a gap in the battlefield with a series of expendable copies. These copies do come at the cost of draining the shields of the original cannons, however, meaning that the player should use them judiciously. Zeratul's Tesseract Monoliths share this ability, allowing Zeratul to project his towers into key battlegrounds.
With the adjustments made to Zeratul made in recent patches, relying heavily on these towers has been made more difficult. The cost of a single Tesseract Cannon is 300 minerals, and the number of starting charges for the Tesseract Monolith was reduced to one. Nevertheless, the cannons remain a powerful option for the player. Proper use of these weapons is key as Zeratul the hero, even with full attack speed mastery and careful micro, is not capable of taking the place of a functioning army, especially on Brutal, and an ally can rapidly become exasperated by seeing Zeratul attempt to solo attack waves and objectives. Therefore, in order to replace the "missing" army, the player needs to produce a mixture of Tesseract Cannons with Xel'Naga Shieldguards to recharge their shields and use projection of the cannons and Legendary Legions very liberally. Xel'Naga Watchers are useful to this build, as they give Zeratul vision that enables him to project his cannons into the battle.
Synergies[]
Protoss Commanders[]
Unlike other protoss commanders, Zeratul does not utilize pylon power and thus cannot benefit from nor provide benefit to other protoss allies in that manner. Chrono boost from the nexus however remains a vital asset. Xel'naga shieldguards are capable of restoring the shields of all allied protoss units and structures.
Artanisremains ever a trusted companion for Zeratul. Guardian shell serves to allow Zeratul's very expensive units a safety net to retreat. High templar or archons with Plasma Surge can be used to charge shields in an area, with shieldguards topping them off. Enforcers provide the answer to all of Artanis's anti-air problems, and pair well with immortals on the ground for dealing with armor. Watchers can be spread around the map for no detriment to supply, giving Artanis the ability to intercept attack waves with warp-ins on a moment's notice.
Vorazunis a great ally to her fellow Nerazim. Strike From the Shadows boosts Zeratul's damage, while Veil gives him stronger shield regeneration. These benefits are also applied to the cloaked void templar as well. Time Stop can be combined with Serdath's legion to quickly strip enemy positions of strong defenders, and Vorazun's normal dark archons can clean up. Zeratul can blink into a black hole full of enemy defenders, use Cleave, and leave them crippled; abrogators can also provide splash damage potential to erase attack waves. Time stop also provides Zeratul a safety net where he can quickly retrieve artifact fragments without fear of attack.
Karax, while not the most obvious of choices, proves a valuable asset to Zeratul, and receives benefit from him in return. Reconstruction Beam benefits all of Zeratul's units save for void templar and Zeratul himself. Combined with shieldguards and shield batteries, this allows all units to remain at full health. Enforcers provide a wonderfully strong ground-to-air unit to make up for Karax's lack thereof, and energizers are invaluable in boosting the effectiveness of Zeratul's force. On the defensive front, tesseract monoliths provide the perfect addition to Karax's already solid static defense, with an AoE stun allowing his cannons and khaydarin monoliths to be more effective than ever in holding a position. Tesseract cannons can be projected in to provide reinforcement should it appear Karax will not be able to hold. Chrono Wave is not as valuable to Zeratul as any other commander due to his lack of timed research, but it still quintuples his production, and thus should be taken advantage of.
Terran Commanders[]
Swann can deploy vespene drones to help ease the expense of Zeratul's high cost units, and Swann's laser drill receives added damage from the dark templar's stealth when moving into enemy entrenchments. Combined with a few science vessels for detection and healing for Zeratul's mechanical units (Xel'naga ambushers and enforcers), Zeratul's army becomes even more unstoppable.
Nova has a similar playstyle and costs with similar offensive and defensive capabilities. Having two cloaked commanders on the field can present challenges, but utilizing Nova's nukes with Zeratul's avatar calldowns creates a surprisingly effective pairing. One major drawback to the Void Seeker is that you can only move Zeratul from one end of the map to the other, but playing off your partner's use of tactical airlift can mobilize both armies to drop in on different map objectives, bonuses, or to easily fall back to take down incoming enemy attack waves. This comes in handy if you're both playing offensively with little base defense. Otherwise, a nice mix of tesseract monolith's and cannons with Nova's turrets makes for a devastating defensive line.
Zerg Commanders[]
Stetmann has a very different playstyle, but his Stetzones can help Zeratul's relatively slow Protoss army move around the field, and can help all of his units regenerate health. Combined with Shieldguards, this gives Zeratul's army unprecedented sustaining power. Stetzones will also regenerate Shieldguard energy significantly faster.
The designers of Co-op have stated that they always had been huge fans of Zeratul as a character in the StarCraft universe, and wanted to bring him into Co-op Missions. However, there was already a “Dark Templar” commander in Vorazun, so care was taken to differentiate him.
The team wanted him both to be on the field as a hero and have a small elite fighting force, as he was most often featured in insurgent-style missions in the StarCraft II campaign, but to go beyond his singular identity as a dark templar. Throughout the campaign, Zeratul looked to the wisdom of the xel’naga for guidance, obsessed with finding their prophecies, and as such the idea to have him hunt xel'naga relics to aid him was made.
In addition, the team was committed to creating a commander that felt and played differently from his protoss brethren. To that end, Zeratul's army was given xel'naga enhancements, with the intention of making him feel as much of a xel'naga commander as a protoss commander.
The Legendary Legion mechanic was inspired by Zeratul's propensity to have allies sacrifice themselves to aid him in the campaign.[1]