Unlike more 'codex' chapters, the Space Wolves put their newest battle-ready recruits into power armour and send them into melee with the enemy to prove their worth. It is odd, but given the 'Wolves nature it seems useful. The Blood Claws tend to be the most psychopathic in combat.
This pack will be lead by a more veteran (and level-headed) great wolf. At least I think that is what they are called, not 100% sure on that one. He is the last of this batch, there might be a couple more things in the 'Wolves' future.