Patron ideas for a lupin warlock?

The idea I have is that someone (not sure of the original race just yet) was attacked and infected by werewolves but due to intervention by some sort of otherworldly being (thinking celestial atm) the curse was stopped. In the process, a pact was formed between him and the being, making him a warlock.

I'm stuck on any further details, such as the specific being that would have saved him.

Could make him some sort of multiclass as well, but I'm not sure, as I kinda want this character to be kind of settled at level 1 so he could be tweaked for any starting level in a possible campaign.