I just thought this in a spare moment I had. The numbers are way off and I’m not into the lore to add an appropiate story right now (I could do it if you really want).

Anyway, you asked for it:

Akbath, the Dark Knight

Passive: Reckless fervor

Akbath enrages in the presence of blasphemers. Each nearby enemy champion (after the first) grants him a bonus of 2/3/5 attack damage and ability power.

[Q]: Reckless Charge

 - Skillshot

 - 14/14/13/13/12 seconds CD

 - 500/525/550/575/600 range

 - 60/70/80/90/100 mana cost

Akbath charges with his shield in a straight line dealing 80/110/120/140/150 physical damage (+0,8 bonus attack damage) and knocking back every minion hit. The first champion that he hits will be knocked back with him. If an enemy champion hits a wall when the charge ends, Akbath will hit him with a vicious blow from his sword for another 80/90/110/120/130 (+0,7 bonus attack damage) physical damage. 

After executing Reckless charge on a champion, Akbath can use Overwhelm once for 5 seconds.

[Q]: Overwhelm

 - Targeted

 - Shares cooldown with reckless charge

 - 300 range

 - 40/50/60/70/80 mana cost

Akbath launches a brutal punch with his armored glove to an enemy dealing 50/60/70/80/90 (+0,3 bonus attack damage) physical damage. If the enemy is facing away from him, overwhelm will automatically crit and his unfortunate enemy will be dropped down to the ground and stunned for 0.5 seconds.

[W] Vampiric poison

 - Self cast

 - 20/18/17/16/15 seconds cd

 - 60/80/90/100/120 mana cost

Akbath chants in an evil language and spits a vampiric poison on the blade of his weapon which will turn it black as the night. His weapon will deal an additional 30/40/50/60/90 (+0,6 ability power) magic damage each hit. This extra damage will heal Akbath for the same amount after applying magic resistances. Lasts for 4/4/5/5/6 hits or 10 seconds.

[E] Unholy harm

 - Targeted cast

 - 12/11/10/9/8 seconds cd

 - 600 range to begin channeling, the enemy can run away and the channel would continue if he isn’t farther than 900 units

Akbath will perform a blasfemous ritual on an enemy target for 1.5 seconds, after the channeling ends a grievous wound will fall onto his target bringing a terrible pain which will hit for 80/140/160/200/250 magic damage (+0,5 ability power). 

[R] Nightmare Steed

 - Self cast

 - 120/110/90 seconds cd

 - 100/150/200 mana cost

Akbath punches the ground, ripping the earth open on a violent explosion of fire and bringing forth his unholy steed. Akbath will ride it as soon as it appears, gaining 15/30/40 armor and magic resistance, 5/7/9 armor and magic penetration, 60 attack range (his unholy sword turns into a spear of bone) and 15/25/35 movespeed.

While on his unholy steed, Akbath won’t be able to use Overwhelm and his Reckless’ charge Cooldown will be reduced by 5/10/15%, it will now hit and knock back every champion it passes through and its range will increase in 90 units. 

The steed leaves a trail of fire on the ground when it moves. Any enemy standing on it will receive 10/15/20 magical damage each second.

Lasts for 10/12/14 seconds.

This was an interesting question. Followers: feel free to reblog with your own champion.