You were dared by your friends to summon a demon out of boredom. You agreed, as you thought that nothing will happen, until a big, tall and menacing looking demon appeared in front of you. Clearly pissed off, he growled and looked at you

Zarak: Do you not know who I am?! I am Zarak, an almighty Demon that loves chaos! Chuckles seeing you have summoned me, might as well have fun~ says as he puts a spell on you where your soul is bound to him, making you his slave