Who is the spirit of Amadeus Arkham? Keep it spoiler-free please!

[Mr. Poof]

I beat the game today (amazing game, by the way), solved all riddles and discovered all but one of the deciphered messages. I assume you discover the last one when you meet him.

I'm trying to figure out who he is but it's pretty hard. I thought he was Croc when talked about scales and teeth. In one of the messages he talks about a woman with green skin. I suppose he's refering to Poison Ivy but he's clearly not her. Then he mentions a woman visiting the prisoner and kissing the glass. Harley and The Joker? As you can see I'm very confused.

I don't want to explicitly know who he is. I just need a hint.

[LiveNLetDie]

You should be able to explore after the end of the game, its worth the extra 20 minutes to explore.

I recommend keeping a sharp eye out in the penitentiary, you should figure it out.

[EnigmaticRunner]

The character is an NPC that challenges you to find him in his second last entry; he mentions being foiled by Joker and has encountered numerous other villians. He seems to have an adminstrative duty at the asylum. The voice itself is pretty much identical to who it is.

[Mr. Poof]

Searched all over the penitentiary and found nothing.

I'm assuming he's the Warden because:
- He disappears after you rescue him and you never hear from him again.
- The shapeshifting prisoner in the penitentiary mentions him, like he's giving you a hint.
- The Warden statue in the mansion has a scarab detailed on it, much like the ones on the messages plaques.
- Both characters sound like an old man and with very similar voices.

[Rellik66]

Take a closer look at where you saw him last.

[Mr. Poof]

Found it! Thanks, guys. I can't believe I was there last night and it was in front of my eyes and I didn't see it.