I've had this Champion as a concept for a while now that works a bit like a couple other champions but is designed to be either a mage bruiser, or a artillery support.
The champion starts out as an undead corpse with low mobility, potentially a previous host to one of the dark kin like Aatrox or just a collection fo the despair of those fallen in battle, but the main point of him is he is a repository of past combats and this shambling shell is just being used to contain their pain and will for vengeance on those who still live. His Q would be a buff that could be used on either an ally champion or on a minion. His W is a mid range ability that can either be used on enemy champions, superminions/cannon minions or jungle creep to reduce both defense and damage for a short time. His E would be a damaging burst with a low cooldown (2-4) but as it ranked up you could wait multiple cooldowns to increase it's power by up to 300% damage at 5 stacks (100>150>200>250>300%) While his ultimate would be a slow moving supression wave out from him, marking champions and letting allies dash to them, a bit of a double edged blade as it marks allies allowing enemies to dash to any marked allies after the suppression. And his passive would decide if he became a spectral artillery support or a Hulking undead mage bruiser, the spectral form increasing his move speed and allowing him to phase through walls towards allies while the bruiser form gives him a bonus move speed towards enemies and a boost to AP and AD based on nearby enemies. And wich form he takes is decided on how much he uses his abilities on either minions or allied/enemy champions.
That is the rough bones of the concept and I tried to come up with an interesting design that would be fun to play, would work with the coming metas and would be a champion not difficult to play but still have a high skill mastery. Something that makes you need to ask, "Is this a good engage?" Both with and against him. I would love critique, and more ideas and concepts for his abilities from BOTH Riot games and our community. Just please keep it mature and civil.