Run away

Frightened, you turn and run, but you feel a searing pain inside your head, freezing you in place. A mindflayer steps into view, its grotesque, tentacled face twisting into something resembling a smile, floating using its mind powers.

Its psychic grip tightens, rendering you unable to move or think clearly. You feel his slimy tentacles brush against your face and head, his touch cold and invasive. Slowly, your resistance fades, replaced by a strange calm. You start to relax and hear the girl’s voice. "You will serve. You will be happy."

And she's right, your master is your protector, you live to serve him and to satisfy his needs. You have a strong urge to offer your body to your master and you accept his slimy, cold cock inside your ass.

The girl masturbates watching you and says that she will breed more mindflayers for his master, and you will help him to explore the pleasure with your ass.

You are a thrall, bound by the mindflayer’s psychic powers, you spend years in the dark of his cave, serving his will alongside the other girl, your mind clouded by a false sense of peace. Your ass is always ready for your master's cock and tentacles, you love when he explores your ass, and when he cums inside your mouth, the cave becomes your world, and the mindflayer’s whisper your only truth.

This lonely mindflayer is an outcast and lives like a hermit, you have a long life with enough food and security at his side.
Decades pass, and your body weakens until you are too old to walk. The girl, now as frail as you, takes your hand and says "We are happy. We served our master as long as we can, but now we must rest..."

Bad Ending
Mindflayer's Thrall ending