[Champion Concept] Xir'Neth the Incorporeal

I think it would be interesting to have a phantom type champion who is either a ghost, or stuck halfway between runeterra and the void, where they have an incredibly low hp pool that cannot be increased through items however they are immune to damage unless they are dealing or have recently dealt damage. This in my mind would create a skill and gameplay driven champion that would be an interesting dueling assassin type.

these are the ideas I think would work well as a possible kit for such a champion.

passive: Incorporeal Phantasm - Xir'Neth is stuck between worlds and leaves a phantom image in his location. attacking or damaging enemies brings Xir'Neth into this world for 3 seconds, damaging enemies refreshes this timer. Turrets will always damage Xir'neth. Xir'Neth gains no benefit from health items.

Q: some form of slightly spammable melee range ability

W: some form of long cd dash that speeds up if used towards and enemy champions and slows down drastically if used away from them

E: 1 second lasting ability shield that blocks next source of non-aoe ability damage, if successful it shortens its cd

R: channeled aoe around Xir'Neth that deals DOT, increasing dramatically the longer it is channeled. is interrupted by zhonias.

anyways just an idea I had that I thought would make an interesting champion who had extra importance on picking their fights and when to cs because they would be inherently super squishy but if used correctly could punish enemies who don't swap target focus quickly.