The third member of inquisitor Kate's retinue (Sisters Pury and Ada were recruited ahead of him).
Usually his behavior can be described as 'You bunch of green arseholes are going to give me a headache again, right?'. Despite the hostile look, Yar is quite calm and even friendly (but only Kate knows about it).
Yar is a natural born survivor. He was a member of PDF on a forge world when it was hit by orks. After the first few days his unit was wiped out, and he switched to guerrilla tactics, killing nobs and disappearing in the ventilation shafts and sewers.
When Salamanders arrived to reclaim the planet, Yar was among a few survivors. Despite his heroic accomplishments, commissars wanted to apply a death penalty because 'If you're still alive, it means that you are coward'. Inquisitor Kate saved Yar by recruiting him into her retinue.
Yar is a master of guerrilla warfare. Sneaking, tracking and silent killing are his best talents. Back in his PDF days he was a sniper, and Kate usually use Yar for 'removing' dangerous targets from afar. Yar uses long las rifle, and Exitus rifle when he has to deal with the tough targets. Yar also uses power knife, poisoned spears, claymore mines and other lethal devices.
Usually Yar wears dark uniform of inquisitorial storm trooper. But he eagerly changes it for something more appropriate according to combat conditions. He likes camouflaged clothes and always wears a chameleon cloak (more like poncho) - a gift from Kate.
Yar uses sophisticated visor/target seeker in the form of an eye patch.
Explosive devices are the second big love of his life. That's why it was easy for Yar to befriend sister Ada.
Usually Yar works alone, carrying recon/assassination missions.