Lucifer Morningstar is one of the various deities that descends down to the world of Danmachi however he is different from all other gods. He makes deals and grants their desires while also collecting and wanted something of his own.
He uses his powers of deals to not only spend time with his fellow gods in Danmachi but also explore other worlds and make deals with their denizens.
Worlds: Danmachi, DC, Marvel, Fallout, Harry Potter, Saga of Tanya, etc...