Sacrificing a portion of your very life, throwing it to the winds in a vain hope of reward that could be either meager or great based on nothing but the whims of fate - Well that's just like gacha, isn't it? Nirou Tetsugawa, a med school dropout, is suddenly summoned to a world where those seeking power bleed for it. Literally. By tributing a portion of one's own blood and invoking the world's god, one will be granted a gift. This can be anything from a fantastic magical ability to an underwhelming basic everyday tool. To survive, Nirou will have to make use of anything he can get. Because if you try to reroll here, you just might bleed out.