Alright, I am tempted to kill him just on principle of humor alone, but can anyone tell me what he was supposed to have drawn/said on the wall?

Heh Its a paradigim. Its an impossibility. Its a Led Baloon. However I will tell you more if you promise not to kill my character.

... Alright, what is it, and what dod you say?

Did it even exist in the 1920s?

Most likely not, which may lead to an anachronistic paradox that makes his head explode...

It did. Don't worry about that. The Symbol on top of the feather is actually three symbols. However that is before its inverted. When its inverted it means "The Hammer of The Gods" in general a reference to Thor. Now nobody is sure what is means upside down because the way the symbol is laid out. Now the feather is "The sacred feather of Mu" which as just a made up race that was tossed around by occultist in the 1880s that was started by supposedly alister crowley. The latin means "All is one one is all" basically an anagram. TODAY however its part of the title of Led Zeppelin 4. as for the words well just spur of the moment. My guy would now most of this through his occult knowledge baisically it would be like a ward.

Still tempted to make your head explode... But I'll allow it.

Whew thanks. I will remember your mercy.

make his head explode

Sorry, he was able to explain away the potential anachronism, avoiding the Anachronistic Paradoxal Head Explosion.