Idea for a Champion

(garbage English incoming) OK, so I had an idea for this couple of weeks. I thought of a champion that could "steal" abilities. Even though that could be kinda overpowered, I think it's a good idea since we didn't had a mage since last year. I think the lore could be kinda secret kinda like Shaco. He could be like an a shaman from an ancient tribe. His Q could be like an AOE damage spell that slows, his W could be an ability to damage enemies or support his allies, his E could be kinda like an E charm that fears them and steals mana. And finally his Ult were he could steal the abilities for a short amount of time.

By the way, it's my first time doing this so tell me what do you think!