Champ idea: A champ who has no damage for himself but buffs another champ significantly

Passive: You have no hp regen per 5, instead for every ally and enemy champ(excluding himself) within 1200 range, you regen 2/4/6% bonus health per second, capping at 10/20/30% bonus health regen per second.

Q: Stops regenerating 50% hp/5 from passive for 5 seconds and instead redirects all of the regen to an ally champion. This effect stops upon death or leaving a leash range of 500.

W: Marks an ally champion for 3 seconds. Within those 3 seconds, the next spell cast by said champion takes mana from this champ instead and deals 40/50/60/70/80% more damage.

E: Costs up to 50% bonus health, upon activation he charges for up to 2 seconds and then causes a pbaoe around him which slows all enemies by up to 50% and roots them if they stay in the circle for 2.5 seconds.

R: Targets an ally champ and wraps self around champ. The champ will take no damage and instead this champ takes all the damage. The champ ulted has total control on abilities and movement. This champ can only use his W on the champ that is ulted and increases the bonus damage by 50%. The W effect lasts 5 seconds from 3. This ult lasts 5 seconds or until he dies.

Thoughts?