Hi again. 
So, my character, Malakai, was a warlord (self-proclaimed king) of a powerful domain within the city of Sodom, which he usurped by murdering his younger brother who was the intended successor. His subordinates attempt to have him assassinated, and while he survives the attempt itself, he is left with a wound that festers and threatens to kill him. 
On his deathbed, he is plagued by visions of meeting his brother in the afterlife/hell, and pleads to God to save him from his fate, but God does not respond. Instead, Malakai pleads with Shamshiel, pledging to conquer the city of Sodom in the angel's name and build a great temple in his glory if only he will rescue Malakai from death.

This is where I intend to have him forge a pact with the angel Shamshiel, but I'm wondering how to perform the ritual in question. I also wonder about the gifts I can receive: I intended to give my character an unnaturally long life as well as the power to cure grievous wounds (including his own) and various diseases and other ailments. This seems within the specified scope of abilities, but I'm asking just to be safe.