So was October a serial Killer?

He's been away a long time, suffering from mental 'monsters' but one main one and is covered with scars , in groups of 5 - which Lance sees and seems to recognise what they mean.

So my reading is that he's become a killer himself for whatever mental explanation you may want to throw out there. Is his weapopn of choice the knife?.... cause all the other 'monsters' at the end all seem to have knives too.