rosestar130

Could they be cured by rendering them permanently deaf?

Theoretically, yes, but they have to be in their human form to be safe.

So if I snap my fingers he turns into a vile and powerful fiend, and if I snap my fingers again the fiend becomes a confused and cowering mortal, ordinary except for having been chosen as the unwilling vessel of this unholy power?

Basically, yes.

Well, I think a common sound would be something you hear every day: car alarm, bell, whistle, etc.

The triggering sound in question is, in its simplest sense, a slowed-down version of the ending of Just One Yesterday by Fall Out Boy [or very similar, that's all I can think of right now]. So, it's not really that common. 

I'm running a campaign where the characters the PCs have to save is possessed by a demon by the evil organization that kidnapped him - and this 'possession' is triggered when the character hears a certain sound and is triggered off by the same sound. I already know the way he's triggered into this transformation [Accidental Change:  Certain Noise Always (Common), right?], but how else would I set this up?

If it's necessary, the demon the character's possessed with has yellow-ish eyes, supernatural strength, and has no moral code whatsoever - he's heartless.

Am I making any sense?

Well, it also makes a difference if you're using superheroic or heroic assumptions.

 

I'd probably do spiked knuckles as a small killing attack. To use in conjunction with Boxing, I'd say you need the Weapons Element.

I'm working under more realistic settings [real-world, slightly different tech] but this works! Thanks!

Before I go on, I will say that I'm using 5th Edition - because it's what I have. I'm also fairly new to the system, too.

Anyway!

I have a character who makes weapons out of discarded instruments - swords made out of broken guitar necks, crossbows out of snare drums with torn heads - whatever he can get his hands on. Though, he makes these for the organization he is a part of and doesn't really uses the weapons he makes. Instead, he uses a set of knuckles with spikes in combination with his boxing.

I was looking through the book, and I can't find it anywhere.

In the system, what are brass/spiked knuckles considered? What'd be their stats?