The Kar'rak, also known as the temple guardian, is an enormous lifeform found on Volteron that killed Yelena while under the control of Maz' Rah. It appears in N.O.V.A. 3 as the final boss alongside Maz'Rah.
As Maz' Rah says, according to legend, "for thousands of years the Kar'rak has judged and separated the worthy from the unworthy", however the true story is that "it is just a dumb, hideous overgrown beast that Psychers play around with and control whenever they feel like it".
It can be defeated by hiding behind the stones when it is using its insta-kill attack and to dodge its tail when it is smashed down towards Kal then attacking Maz' Rah when he appears. If you kill Maz'Rah, the self destruct system that Yelena placed will kick in and destroy the Kar'rak.
-It bears several similarities to the Korakk Beast from Metroid Prime 3:Corruption.