A potentially interesting idea, especially with the Coagulate passive and active. You're right, the ult doesn't fit, but the champ in general does not fit as an assassin. His W gives zone control, his E gives an auto attack buff, his Q gives aoe damage (maybe waveclear), his ult gives a large heal. The kit is entirely incoherent and the only synergy is between the Q and E (a very minor buff).
For starters, if the champ should be an assassin, add an option on W for killing champions, or any unit, and allow him to snowball kills off of that like Jinx or Draven. Whenever he kills any unit, it turns into a statue of blood. Once activated, all nearby statues detonate, dealing aoe damage and slowing enemy units. He gains a stacking movement speed boost for each pillar that detonated, up to a cap of 200%. Killing an enemy champion resets the cooldown on this ability. This gives him some reset assassin potential and chasing power while preserving the more unique aspects of his kit.
Allowing him to stay alive once he dives in, because of a lack of instant deletion skills or quick jumps, is also important. Making his Q less of a simple damage dealer and more of a sustain tactic can fix this. Damages self to damage all surrounding enemies and gain a shield based on how many enemies were hit. Applies Heat Up to all targets. This adds risk/reward play to his standard aoe damage.
The passive, E and ultimate are pretty inane, but it could be more interactive. Sure, stat-only abilities can be strong (example: Mundo) but it doesn't necessarily make for more interesting gameplay. For example, moving the Heat Up to the passive slot opens up space for one more ability while making the "blood boiling" part of the kit integral to the "Blood Boiler". His basic attacks set the blood of his target boiling, applying Heat Up and dealing % health damage over 3 seconds.
This means that we can add another spell in the place of E. To fill the role of the passive attack speed buff, we can give him a new spell which ties into the passive. While toggled he becomes Hot Blooded, steadily losing health while gaining increased attack speed based on the number of nearby targets with Heat Up. Killing a unit with Heat Up restores a % of his health and grants additional movement speed. This gives an enormous attack speed buff that synergizes with his Q and passive as well as facilitating additional resets.
And what about his ult? Well, we have an attack steroid, a dot, an aoe, and a slow/speed boost. If we assume half decent ratios, he still doesn't quite have enormous burst so much as a rush of sustained damage and reset rampaging. So should we give him burst or more sustain? Well, Cauterize gave a huge burst of health, so why not give some Sivir-like team steamrolling? He heals all friendly champions and himself for a % of missing health and grants all surrounding champions his movement speed bonus. This way, Blood Boiler's entire team benefits and gets to come along for the ride as he tears through the enemy team.
All in all, your concept was full of good ideas, but somewhat lacked a coherent role and the strengths of an assassin. Giving him a powerful, Tryndamere-like, Master Yi-like steamroll potential and presence. I hope you don't take much offense from me revising your ideas. Keep working on this concept and have fun making champs :)
Reviewer, away!
