My mind is so cluttered, and yet... it is completely empty.
His true personality is quiet and gentle, but the asylum he was thrown into drove him... well... insane. He breaks sometimes. Especially when he is sent into the blackness behind the Reaper gate to call Avis out. The shadows there will drive anyone mad, but he opts to go because he already us.
He fights with Screamer. He might as well; he's already insane. He also rather likes his silverware. Spoons and forks, preferably.
Thrown in an asylum die knowing too much of the business of his underworld employer, the place drove him mad. He would have broken completely, if Avis hadn't gone in and saved him when he did. Thankful for that, John devotes everything to Avis.