Definitely an interesting champion mainly for how she was changed into this by the mists of the shadow isle (I had a similar idea myself for a new champions I was making, but never went through with them yet).
The only issues I see, currently, is the damage and the Q.
Currently the damage just seems really high, or perhaps it's all the things which affect the damage. Since she has base damage, % missing health, and AP%. Her heal has 4 things affecting it. Base heal, AP %, Enemies % missing health, and her % missing health. That's a lot of heals. Something you'd expect from a sustain such as Vlad.
The passive. I'm guessing 32 is the base at lvl 1 and gains base damage from the 6 X champ level right? So at lvl 18 that's 140 base damage. So, at 600 AP (highest AP I've gotten on a pure AP build before so I'll use that) that does an extra 180 magic damage. So 320 damage to all enemies already with magic damage (including the one you shot). So, not only does the target take your Basic Attack Damage but the passive damage. Which stacks since there are 3 slugs, so that damage is multiplied by 3. So that 320 x 3 is 960. Almost 1k in damage with just her passive at lvl 18. That's high even late game. This is not taking into account the % missing health. Which could further increase the damage. That missing health can range anywhere from 50 (missing 1000 health) upwards to 150 (3000 missing health, usually from tanks) and both are multiplied by 3 if hit with all 3 slugs. So...that's a lot of damage. Just saying. And to all enemies along its path. What I'd personally do is lower the damage per slug that hits them. Meaning that each consecutive slug deals less damage on the same target if they are hit with more than one slug.
The ults damage...I'm guessing this is targeted. So, it's already easy to hit and no counter. Just click and BOOM. Possessed and damaged at max rank for 600 (+40% AP). Depending on if you're going hybrid or full ap that damage could be 600 + 120 or 600 + 240 (using 500 AP, the most I've been able to get without using Veigar who can stack AP and before the game ended). So that's an instant 720-840 damage (taking no MR into account though, so MR may take some damage off). After words any damage done to you is done to them. 100%. That's even MORE damage. If your health is 2500 (easy with RoA and a few other AP health items) and you take 1500 damage from whatever, that's 1500 damage done to them. THEN when you leave the possession they take 50% of their missing health. So if they started at 3000 health they're already down to like 500 or so HP. So that would be 2500 missing health. Half of that is 1250....aaaaand they're dead.
So unless they are stacking a shit ton of MR (which isn't always reliable since I've had 3000+ health and 200 + Mr on tanks against mages and STILL get shredded by their spells in seconds) and don't attack her at all...you're pretty much screwed if you're hit by this which since I imagine it is a targeted ability and not a skill shot has no counter to it.
So as you can see, it's a lot of damage that is damn near impossible to avoid. Anyways, on the Q.
This thing...I want to ask this question. What kind of damage and things can this spirit do? Can it do 100% full damage and all the abilities of her? If so....that is one of the most OP abilities out there. I say this because she can just in safety whether that is behind a turret or by teammates protecting her, cast her Q and just rush into the middle of enemies and unleash all hell without any repercussions since the spirit is invulnerable. Sure, if they can get to her body they can hurt her, but at 25% reduced damage and all while taking fire from a turret or her teammates. Now, late game this is easier to dive turrets due to tankiness, but early game? OP as all hell.
Sure, the 6s limits the time, but that's 6s of pretty much free damage. No one early game (unless they are godly) are going to dive into a turret or into a group of other champions to attack her, and attacking her doesn't even end the ability, but if they DO get close to her, she just replaces herself with the spirit which explodes. I see very little counter for this unless silences break the link or any amount of hard CC on her body can break the link, and while her spirit is invulnerable can IT still be affected by hard CC or can it not be targeted at all?
Just a few details I have questions about.
So overall it's an interesting concept. I like it personally, but the damage and heals on a few things are just very high and almost unavoidable. It would be extremely hard to counter her imo. So tweak the damages a bit and add a bit of info on how these abilities can react through the game and can be countered. Currently there's not much that can be countered in her kit. Countered easily anyways.
On a completely different note....I was going to use this picture in a champion I was making. T_T RIP. I saw this picture a few weeks ago and thought it looked amazing as a champion design. So I might use it still, but just wanted to let you know I didn't rip the picture from your concept D: I just saw it through the interwebs a few days back.
Anyways, good job on the concept and continue working on things! Practice makes perfect they say. :P
