[Work in progress] Support Idea (Name Pending.)

Here is the idea of a support that came to me while I was playing a game. I asked the chat and they said it had the potential to become bad ass. (Paraphrased.)

The goal here is to create something unique and fun.

Physical description: This character is a shadow that has come to life, following his teammates on the ground to pop up and slash at the enemy.

Abilities: Passive - [This character] has to be attached to an allied champion, becoming their shadows and immune to damage. (He can switch freely between allies - global range) The ally that he is attached to gets bonus to their AP and AD. (Perhaps AD and attack speed instead?) If the ally he's attached to dies, he sprouts up and becomes his own being, quickly draining his HP until he finds another being to possess.

Q - [This character] slashes out in an arch, dealing a small amount of damage (AP scaling) and slows for [x%].

W - [This character] calls upon the shadows to shield the ally he's attached to. This takes away from his own HP pool. (Similar to Janna's.)

E - [This character] plants spikes of shadows on the ground, instantly damaging anything in the area and slowing anything in that area for [x%]. (The idea is the slow, not so much the damage.)

R - [This character] possesses target enemy champion, darkening their surroundings (think like Grave's blind or Nocturne's ult) and dealing [x] damage over the duration. Once the duration is over, [this character] sprouts out of the ground and becomes their own being, quickly draining in HP until he possesses another being.