Colossus

The colossus is a massive protoss robotic walker. It is designed to destroy large numbers of weaker ground targets.

The plural of colossus is colossi.

Overview
The colossus is an antiquated protoss war machine, dating back to the Kalath Intercession. It is a towering construct, striding across the battlefield on four tall, slender legs which give it an extremely high level of mobility. The great height of the machine allows it to step up and down cliffs and other steep elevations with little difficulty, and gives it a dominating field of fire. The heavily armored hull of the colossus carries two powerful thermal lances: one mounted on each side of its body. Complex focusing and targeting systems are used to pinpoint the continuous damage output of the thermal lances for optimal efficiency. A colossus's beam cuts a fiery swathe of destruction through multiple enemies with each firing cycle, able to reduce a group of marines to ashes in an instant.

The colossus can be transported by the warp prism, which transforms it and other transported units into energy.

The colossus is feared for being a war machine, and some protoss believe they cannot be controlled and could turn against them.

History
The colossus is unique in that it was created purely as a war machine, in contrast to most protoss automatons which were mainly created for industrial and/or resource gathering purposes. Such a trait was demonstrated by the mass slaughter carried out against the kalathi, appalling the protoss. As such, the Conclave outlawed the manufacture of colossi, and existing machines were deactivated before being sealed away. Some were sent to distant asteroids and uninhabited moons. Others were stored on Aiur, some underwater, awaiting a reactivation signal. They weren't reactivated in time for the war on Aiur because it would take too long.

The war against the zerg, however, prompted the return of the colossi to the protoss arsenal. In 2503, the protoss began collecting them using coordinates collected from a preserver, despite misgivings.

In 2504, Dark Prelate Zeratul traveled to Aiur and reactivated some colossi as part of a mission to study the body of the deceased Overmind. Later that year the Tal'darim used them as well in their defense of a xel'naga temple on Xil.

Game Unit
Colossi are not strong for cost and require support, such as a front line of s. They are strong against s, zealots, hydralisks and s, but weak against thors, immortals, s, and anti-air units like the viking, phoenix, and corruptor.

Height and Climbing
The colossus appears to step over ledges due to StarCraft II's inverse kinematics (IK) system. It can climb ledges only one level at a time and is blocked by taller cliffs. It can also step over smaller friendly units, but not other colossi or obstacles. Like other massive units, the colossus can collapse a Force Field simply by being ordered to move through it.

A colossus is tall enough to see the tops of cliffs, enabling it to climb them and fire upon the high ground without a spotter.

The colossus' height enables anti-air attacks, such as those of the missile turret, to strike it (even though it is a ground unit). Blizzard has confirmed that this is because the colossus is so tall that it counts as both a ground and air unit for the purpose of what attacks are able to hit it. If an attacking enemy unit (such as the thor) which can attack both ground and air units attacks a colossus, it will use whichever attack is stronger against the colossus.

Attacks
The colossus attacks only ground units.

The attack animation is a sweeping beam, with the animation taking about a second to complete. All targets continue to take damage simultaneously. The attack always strikes a linear area perpendicular to the direction the colossus is facing. This allows for a fine degree of control.

The attack does linear splash damage which is very effective against groups of units such as s and s. It is safer to use colossi against terrans rather than psionic storms, since s counter. Against zerg, colossi are very effective against s which have become more dangerous with roach support.

The beams do not have a "blind spot" and can strike enemies right next to the colossus.

Wings of Liberty
Colossi are usable in the StarCraft II: Wings of Liberty protoss mini-campaign, available after the "Echoes of the Future" mission, Zeratul finding some on Aiur.

References/External links
Coloso