Avatar of The Watcher

Any creature who possesses the Obsidian Gaze can cast this. For the 5 turns of casting, you can perform no actions and have vulnerability to all damage as one eye glows with brilliant light, blinding every creature nearby, even those who would be otherwise immune to blinding or the light. After the 5 turns pass, you must state the true name of The Watcher, at which point he is absorbed into you via the Obsidian Gaze and you gain all his abilities, features, and effects, and knowledge. However, you must make a DC 50 Intelligence saving throw or be taken over by The Watcher, him obtaining your knowledge and body. The DC reduces by one for every day you have possessed the stone or been in the presence of The Watcher, but raises by 1 for every day you spend away from the objects until it returns to 50. The DC cannot be reduced below 20 regardless of effects. If you succeed in casting the spell while the DC is 30 or lower, your mind and The Watcher's remain separate, and you can communicate and interact with his mind as if it were a creature using telepathy. If you use this spell and do not lose yourself, your body is blessed by arcane magic, which improves your bodily condition to that of the Watcher's in his normal life, but you are simultaneously cursed by divine magic due to casting a 10th level spell, preventing you from casting divine magic and causing you to be shunned by the gods.