Name: Karthen
Race: Rachni.
Gender: Rachni Male.
Age: Unknown.
Alleginance: The Hive.
Status: Rachni Brood Warrior.

Appearance:
Karthen is a large, grey-white coloured Rachni Brood Warrior. He has red eyes, for reasons unknown. He also has a bullet wound in his back leg from an encounter with a Human.. it has since been healed and is meerly a scar now.

Bio:
Karthen was one of the first of the 'New Generation' of Rachni.. he hatched in the first few eggs layed by the queen released on Noveria by Commander Shepard. His scar on his back leg was obtained by attacking a Human that strayed near him once.. he had lashed out and missed, the Human had shot him in the leg with a black object that made a loud bang.. it had started Kareth, he immediatly killed the man after.

((Added more Bio :P)

I would say you need a little more Bio, but hey a Rachni is a odd creature.