The demon scam

Terrified, you see the hyenas close in on you. You realize you won't stand much chance fighting them off by yourself, and you can't really outrun them either can you?

Things cannot get much worse right now, so you reckon you don't have anything to lose by calling for help. Perhaps there is a chance of a good creature out there listening...

"Someone! Please help!!" you call out as loud as you can.

(What letter do you have to remember?)