Spear

But never had Bjorn seen Russ fight with such savagery.
A wolf fights hard, but it fights carefully. Injury to an animal is a death sentence. Ordinarily Leman Russ fought like an animal, with savagery that was nonetheless tempered. Upon the Vengeful Spirit he abandoned restraint completely. He fought like a baresark. He wore his fury and his pain openly. For the first time since Horus had spat on his oaths of loyalty, Leman Russ faced the treacherous sons of his brother. The Spear of the Emperor buzzed through the air in wide, deadly sweeps, its leaf-bladed head opening armour like paper and destroying the bodies beneath. He cast it with such force it pierced its targets, killing them instantly, and always he ran forwards right into the enemies' guns to retrieve it, as if this once much-hated weapon had become dear to him.

Wolfsbane