Zurvan

Zurvan (or the Ancient One) was a primal zerg of Zerus who had lived for millions of years. He was spawned before the Overmind, and lived to see the return of the Zerg Swarm to Zerus during the Second Great War. It shepherded a deinfested Sarah Kerrigan's rebirth into the Swarm, before challenging her and subsequently being killed and having its essence absorbed by her.

Biography
"An elder and powerful creature. Ancient and wise beyond the understanding of Kerrigan or any of her cohorts. He is cold, mysterious and calculating."

- Character description

Zurvan was younger than the power found in the first spawning pool but older than the first Overmind. It escaped being incorporated into the Swarm hive mind by Amon and remained on Zerus when the Swarm left the planet. In time, it became a pack leader and became immense both in power and physique. By the time the Swarm and a deinfested Sarah Kerrigan returned to Zerus, it had been millennia since Zurvan's last evolution.

On the advice of Zeratul, a protoss Dark Templar, Kerrigan sought out Zurvan to help her claim the power of primal zerg. The Swarm fed Zurvan quillgor to awaken it. The primal Brakk and its pack unsuccessfully attempted to halt the awakening. Zurvan instructed Kerrigan in the ways of the primal zerg and the ancient history of the zerg. Most importantly, it directed her to use the first spawning pool to transform into a primal-based human-zerg hybrid; the new form was more powerful than the old Queen of Blades.

When Kerrigan came to Zerus, she was far less powerful than Zurvan. Once a reinfested Kerrigan killed and absorbed the essences of the other pack leaders, she became worth consuming. She expected Zurvan's challenge, and killed and absorbed its essence as well.

Gameplay
Zurvan appears directly after killing Slivan and receiving units to control. He will burst out of the ground, leaving a crescent shaped battlefield with his head in the center and tentacles on the exterior. The first stage consists of him smacking the ground with multiple tentacles dealing large damage, and spitting out zerg minions.

The second stage which comes up when he's at about a quarter health consists of him blasting a portion of the stage (near Kerrigan's last position), leaving energy pools that damage you. His attacks take some time to charge, giving you time to avoid it.

Development
Zurvan was the last thing Phill Gonzales worked on for Heart of the Swarm, and the modeling, texturing, and animation for him took 3 months to complete. His creation began with a rough sketch by Trevor Jacobs on a whiteboard which showed a really distinct head he had in mind for a mission mechanic. Luke Mancini then did a multitude of concepts exploring what Zurvan's entire body looked like to match Jacobs's head design. All of the concepts explored many different ideas which were cherry-picked to be used on the game model. Some more dynamic ideas had tentacles coming out of the back and underneath Zurvan instead of legs.

As his scale in-game was gigantic Zurvan had many details that needed modeling and potential design ideas were up in the air for his role in the game. The developers intended this model to be usable for multiple phases of an encounter. Only once Zurvan's texture was well underway did the developers realize his resemblance to Mr Waternoose.

While Zurvan was always intended to be the final boss of the Zerus arc, he was originally one of many Ancient Ones. These beings were cut during development.

Personality and Traits
"No allegiance but to self. Kill or be killed."

- Zurvan

As a primal zerg, Zurvan embodied the "survival of the fittest" ideals the pack leaders operated on. Zurvan was wary of the hive-minded zerg swarm, believing that losing ones individuality to a single will is a terrible fate for a strong zerg.

The 'wings' on Zurvan's back stored energy, akin to the plates of the stegosaurus of pre-historic Earth.

Trivia
Zurvan may be named for Zurvanism, a branch of Zoroastrianism that worshipped the deity Zurvan as the first primordial creator.

The battle against Zurvan is similar to the boss fight against Belial from Diablo III.