Donnie is the founder and leader of the organization, which is struggling with different groups of bandits and bastards. Once such people killed his younger sister Kristen. She was twelve, and the bandits did it just for fun.
And this incident is the reason why Donor hates them. Hates so much that he is ready to destroy their associations and just kill them one by one.
Of course Donnie had never sat on a pile of corpses in his life. This is a symbolic picture.
All bandits are sentenced to death from his blade or blades of his people.

Sorry for my bad English :C