Mannoroth by RobboMcjobbo

Passive
Mannoroth's basic attacks deal damage to all units in a 180 degree arc in front of him for 50% of his basic attack damage. Each hero hit by Fel Cleaving offers 2 stacks of Fel Endurance, and basic attacking a hero directly will offer 1 stack. Each stack provides Mannoroth with 15 additional health. Fel Cleaving does not hit the focus of the basic attack.

Quest - After reaching 20 stacks of Fel Endurance Mannoroth will gain 3 health regeneration per second. Repeatable.
Every 200 stacks of Fel Endurance Mannoroth gains an additional 7 health regeneration per second.

Cooldown: 12s
Mana cost: 50
Engulf a target in Fel flames, dealing X damage per second to the target for 5s, melting their armour and reducing it by X per second, up to X. Enemies nearby to the primary target receive half of these effects.

Cooldown: 16s
Manacost: 65
Let loose a terrifying howl that reduces nearby hero damage by X% for 5s. Increases Mannoroth's basic attack damage by X% per enemy hero hit, lasting for 10s.

Cooldown: 12s
Mana cost: 50
After a 0.5s delay charge forwards a short distance, dealing X damage to all units caught. Mannoroth is unstoppable during the dash, and passes through units. Does not pass through terrain.

Cooldown: 90s
Mana cost: 100
Gaze upon a target enemy hero, forcing them to move towards you. Once the target reaches you deal X damage to the primary target and all other enemy units in front of you. You are unstoppable and unable to act during the gaze.

Level 20 talent Execution - Targeted hero gains X% movement speed, and cannot be slowed, rooted or knocked back. Upon reaching you the primary target is rooted for 1s, and all secondary targets are knocked back. If the target is the only hero hit, they will suffer X% additional damage and are stunned instead of rooted.

Cooldown: 120s
Mana cost: 100
Mark a target hero for Doom, dealing X damage every second for 120s. Each time it deals damage the damage increases by 5% of the previous damage, with a minimum of 1 extra damage. If the target dies during this time a Doomguard will be spawned. Can be removed early by having the target healed equal to X% of their maximum health.

Level 20 talent Sudden Doom - Doom deals double damage. Duration and cooldown reduced by 80s. A Doomguard is now spawned every 20s, and mana cost is reduced by 60.

After 0.75s Mannoroth's feet glow green with fel flames, allowing him to move 30% faster.