Gul'dan by KnowThyself

Tier 1

Dark Harvest: Health and Mana restored by Harvest Souls increased by 50%.

Tides of Darkness: Permanently gain 5 Health when an enemy dies nearby.

Mana Feed: Felstalker Mana cost reduced by 100%. Felstalker attacks restore 5 Mana.

Dreadsteed: Your mount is replaced with a Dreadsteed which provides 50% increased Movement Speed. You can mount the Dreadsteed instantly and will not be dismounted by taking damage. Cooldown: 30 seconds.

Tier 2

Amplified Healing: Increases regeneration effects and all healing recieved by 30%.

Immolate: Spells and Felstalker attacks cause enemies to burn for 30 (+6 per level) additional damage over 3 seconds.

Gathering Power: Passively grants 5% Ability Power. Each Hero takedown increases this bonus by 2% to a maximum of 15%. This bonus Ability Power is reset to 5% on death.

Envenom: Activate to poison an enemy Hero, dealing 179.96 (+29.92 per level) damage over 10 seconds.

Tier 3

Soul Leech: Chaos Volley and Hand of Gul'dan activate Harvest Souls when they deal damage.

Fel Hunger: Felstalker Movement Speed increased by 30%.

Shadowfury: Hand of Gul'dan stuns enemies for 1 second.

Shadowburn: Chaos Volley deals 50% more damage to enemies below 50% Health.

Tier 4

Nether Portal: Summons a Nether Portal which will periodically spawn waves of 3 Chaos Imps to reinforce the nearest lane. Limit of one portal. Cooldown: 5 seconds.

Doom: Afflicts an enemy with Doom, which will heavily damage them over 5 seconds. If the target dies, a Terrorguard will be summoned to fight for 60 seconds. Cooldown: 60 seconds.

Tier 5

Embrace Chaos: Gain a stack of Embrace Chaos when an enemy dies nearby. Stacks are consumed by casting Chaos Volley. Each stack causes Chaos Volley to launch an additional missile at a random nearby enemy. Maximum of 3 stacks.

Rain of Fire: Hand of Gul'dan deals an additional 60 (+18 per level) damage to enemies in the area over 2 seconds.

Felguard: Your Felstalker now spawns a Felguard which takes 30% less damage from non-Heroic sources of damage and deals area damage with attacks.

Shadow Bite: When used on enemy Heroes, Felstalker instantly deals damage equal to 6% of the Hero's maximum Health and Silences them, making them unable to use abilities for 1.5 seconds.

Tier 6

Fel Domination: Felstalker gains an additional charge.

Eradication: The cooldowns of your Basic Abilities are reduced by .5 seconds each time Harvest Souls is triggered.

Devastation: Hand of Gul'dan impacts .5 seconds faster and has a 15% larger radius.

Soul Mastery: Decreases death timer by 30%. Harvest Souls provides 50% of its Health and Mana regeneration instantly.

Tier 7

Certain Doom: Doom will summon a Terrorguard regardless of whether the target dies.

Imp Horde: Increases the amount of Chaos Imps spawned by Nether Portal per wave by 2.

Stormreaver: Health will be used to pay for the remaining mana cost of Abilities if Mana is insufficient. While below 50% life, your Basic Ability cooldowns regenerate 50% faster.