[CONCEPT] Health-cost support?

Personally,I like health-cost champs like and , but they are always tanky, and self oriented, since they have to take more time to think about their ability costs as they can bring themselves down to as little as 1 hp. I think that a support on a health-cost system could be really interesting to play. I don't know about exact stats, or whether some of these ability's should be passives, or ults, or anything in-between, but here are my thoughts on some powers they might have.

%of damage dealt by nearby allied champs returned as health

This would give the lifesteal potential needed to keep a HC champ alive, it would go well together with some ability to boost allied damage. If it were single target or channeled, the % could be relatively high, like between 40 and 60-ish, but if it were passive, it would need to be scaling, up to something around 15 to 20% at lvl 18.

Single target damage boost

This could be targeted on ally or enemy, dealing some flat damage rate and marking them for extra incoming damage for a short period (+% of missing health) and on allied cast give them flat bonus(+%caster AP)(+%target AD/AP). On allied cast the % bonuses would have to be pretty low, like in the 5 to 10 range. I think giving both of these target options gives this move high utility, like casting it on a high damage ally in a dual scenario or teamfight, and casting in on an overextended enemy in a gank or bait. This is intended to go hand in hand with the concept stated above. It should consist of a % health cost, mostly because of its usefulness and (if used correctly) positive health returns.

Chunk damage shield

Basically, giving up your health to bolster an allies. Think of 's bulwark, but with a health cost. It should give a % of caster's armor and MR, adding a level of build depth. Is it more beneficial to stack on AP for damage? or perhaps on defense to buff the shield. Optimizing for defense against specific team-comps would also be a factor. A infused shield won't be helpful against a full AP team. You would also have to think ahead to the late game. For example, if your getting stomped by a , but your other 4 opponents are mages, defensive items helpful for you may not be as useful to your teammates later on. You could build strictly for the shields benefit, or ignore it completely and build for damage. This should probably have a flat health cost.

Mobility

A champ like this has the ability to be tanky, but has high ability costs that are optimized for teamwork. This means that in anything other than a Break-The-Meta positioning, he or she would be somewhat squishy, and EXTREMELY high priority. So it would need some kind of dash, preferably that could pass terrain, but with so much to offer in ally buffs, it probably wouldn't so that the champ didn't have every possible utility. Should have a low cooldown, deal small damage and be a % health cost.

Possible ult

This kind of chance has an extremely high risk, high reward playstyle, and what could complement this concept then an ult that can actually kill you. The concept is, that once activated, the ult can not be turned off, but will end in 8 seconds, you begin losing health at an incredibly dangerous rate, however, all your abilities are cost free and you are immune to outside damage (excluding fountain) , so if you can decide who to shield, who to boost/debuff, and who to AA, you can potentially turn the tides of battle, however it is an incredibly skill based tactic, so you shouldn't use it unless you know you can win with it, or are going to die anyway(#YOLO moments).

Summary

In the end, balancing the numbers and % would be key in making this a viable champ, builds will also be especially important. He would benefit greatly from items like , , ,and

This is just a thought i had, but feedback is appreciated, if i feel that something said in the chat is constructive, i will edit the post, thanks for reading!