Champion Concept: Vexus the Void Knight

Note: A lot of the numbers are pretty random in the essence that I would not have an idea of what is balanced just offhand exactly, it's mostly about the mechanics that the champ would have. Some numbers and scaling are just not included for even a guess.

Maybe it could be a Hybrid champ - bonus ad scaling but attacks do magic damage. Although might be op since it's hard to itemize vs.

Vexus the Void Knight (uses the power of the void like Malzahar and Kassadin , but is a more brawler type knight)

Passive: Shadowy Affliction Vexus' abilities and auto attacks cause the enemy to take 2% of their missing health in damage per second, for 3 seconds, stacking up to 3 times.

Q - Darkness Approaches - Vexus rushes to target enemy and impales them (dealing X/X/X/X/X damage(+%AD scaling w/rank)), causing a status affect called dark torment which doubles the damage taken from his passive. Darkness approaches can be used again without affecting the cooldown of the next for the next 3 seconds, in which he can jump to a target with lower health than him only. Darkness Approaches is both a targeted skill and a skillshot, and if you target past a certain range it will become a skillshot where instead of charging directly to that target, it will be a thrust in that line damaging targets near the end of his sword.

W - Void Gate - Vexus summons a portal which lasts for up to 3 minutes and from it he can summon 3 shadow soldiers every 25/20/15 seconds. Shadow soldiers are untargetable, last 7 seconds and and move quickly to damage a chosen target (by pressing W again, you can only close gate by moving away from it or channeling to close) (damages when they reach melee range) for X% of their current health when w is pressed again, and they apply a stacking debuff which slows the target by 20% per soldier that hits the target for 3 seconds. Vexus can close the portal if he clicks and channels for it to be closed (1.5 second channel), or if he dies. There is also a leash range in which it is automatically recalled.

Summoning a new portal is instant.

E - Assaulted Soul/Demonic Grasp (both just name ideas, although could be something a bit more voidy) - Sends a shadow line skillshot that binds the first target, causing it to be rooted it in place for 1.5/1.75/2/2.25/2.5 seconds and dealing damage. The rooted target explodes at the end, which deals damage in an AoE around the target as well as to the target. If the target is the only one hit by this damage, it will do bonus damage.

R - Dark Arena - 600 range Vexus and the enemy target go to the dark realm equivalent of summoner's rift, where no one can target or see them for 4/5/6 seconds. Vexus gains 25/35/45% attack speed, 10/15/20 armor and magic penetration, and 25/30/35 attack damage against the target and 3% movement speed when approaching them.