"Is that fear, Yagdra? You do know you never had a chance, right?"
"Your change means nothing! I will melt the flesh from your bones!"
- Yagdra and Kerrigan verbally spar(src)
Yagdra closely resembled an ash worm in appearance, and it was considerably larger in stature than most other primal zerg. It could spit gobs of destructive acid that, according to Zurvan, burnt like fire.
- Character description(src)
When Yagdra learned that Sarah Kerrigan was transforming in a chrysalis, it attempted to halt the process permanently by sending its pack at Kerrigan's brood. In the process, Yagdra also eradicated the last remnants of Brakk's now-leaderless pack, however, it was not successful in killing the Queen of Blades before she hatched from her chrysalis.
The opportunity came soon enough, however, when Kerrigan, now the Primal Queen of Blades, set out to challenge the pack leaders for control of Zerus. She came for Yagdra first. Aided by Dehaka's Pack, Kerrigan fought her way through Yagdra's minions and confronted the pack leader himself. Yagdra told her that her transformation meant nothing. The two fought, and Kerrigan emerged victorious. After slaying Yagdra, she absorbed his essence. 
Yagdra spits acid in two forms, a prolonged linear stream, and rapid explosive bursts strewn around the battlefield. Both show the path of the blasts before they hit.
He also has the ability to dive under the ground, leaving behind eggs in the process. They can contain either lots of small primal zerg units, or a primal ultralisk and small units. After a second he'll jump out of the ground again.
Like Dehaka, Yagdra appears to be damaged and is missing some parts. His left tusk is broken off approximately halfway down and his left arm appears to be partially burned or melted as it has some of his bones visible under his skin.
- ↑ Blizzard Entertainment. StarCraft II: Heart of the Swarm. (Activision Blizzard). PC. Credits. (in English). 2013.
- ↑ 2.0 2.1 2.2 Blizzard Entertainment. StarCraft II: Heart of the Swarm. (Activision Blizzard). PC. Mission: Heart of the Swarm, Supreme (in English). 2013-03-12.
- ↑ Blizzard Entertainment. StarCraft II: Heart of the Swarm. (Activision Blizzard). PC. Mission: Heart of the Swarm, The Crucible (in English). 2013-03-12.