“The other pack leaders are a rock, a tree, a hill. They will stand against the wind. They seek power. I am a river. I flow. I seek essence.”
When the Zerg Swarm moved on to new planets with renewed ambition caused by Xel’naga interference, a small group of zerg stayed on Zerus. Evolving on their own for centuries, these Primal Zerg had an ecosystem of their own when Kerrigan landed on Zerus with her own swarm. Dehaka was one of them, he had recently lost his big right arm, looking to collect essence and evolve himself. His survival instinct was apparently stronger, considering how he asked to join Kerrigan’s swarm and offered aid. While the other pack leaders had been falling one by one, Dehaka had already accepted the fact that Kerrigan was the strongest. Zurvan, Yagdra, Kraith, Slivan and others were obliterated before this union, while Dehaka and his pack adapted, survived and evolved with the essence of the fallen. Staying with Kerrigan, he made sure he would have more essence to collect.
When Kerrigan’s swarm arrived at Terran Dominion’s Skygeirr Station, Dehaka felt different essences and enthusiastically he tried to assimilate the Protoss-Zerg hybrids. As his efforts proved fruitless, he came to realize how terrible the creations of Amon were and more importantly, that they could destroy all collectible essence in the galaxy. This revelation turned into a self conviction to fight with Kerrigan with everything he has. When Dehaka joined Kerrigan’s effort to save the terran Jim Raynor for reasons Dehaka failed to see; the primal zerg had a run-in with Kerrigan’s prominent brood mother Zagara. Since Kerrigan forbid Dehaka from gaining essence from the prison zone, Dehaka had to work with the Terrans.
The last phase of Kerrigan’s revenge on Korhal was an open buffet for Dehaka and his pack. While Emperor Arcturus Mengsk’s psi destroyer severed the psychic link of the zerg swarms, the primal zerg, without any such links, were left untouched. This allowed the pack to sabotage the machine and allow Kerrigan’s swarm into Augustgrad. Following their sabotage, they joined the main forces in the final assault against the Palace in Korhal.
Little to none is known about what Dehaka did after Kerrigan was free of Mengsk’s shadow and the swarm was liberated. It is likely that they found a world rich with essence to keep adapting and adapting…