Shadowreaper Anduin by Funk_Engine

Piercing Headache:
Quest: Hit enemy heroes with Mindblast
Reward: After hitting 15 enemy heroes with Mindblast, Mindblast also applies a 1 second blind.

Siphoning Lash:
After casting Spirit Lash, Anduin's next basic attack deals bonus damage equal to the 50% of the basic attack damage of the original target of Spirit Lash.

Peace and Quiet:
Silence also lowers the target heroes spell damage by 10% for 1 second. If the target was channeling an ability, the spell damage penalty is doubled.

Echoing Void:
Hitting a Minion with a Voidform enhanced basic attack reduced the time for Anduin's next basic attack by 0.25 seconds and refreshes the bonus from Voidform.

Spirit Dampener:
Spirit Lash also applies a 30% fading slow.

No One Can Hear You Scream:
Anduin's basic attacks deal an additional 60% damage to silenced targets.

Enfeeble:
While being damaged by Spirit Lash, targets deal 40% less damage with their basic attacks.

Confuse:
Enemies hit by Mindblast take an addiitional 2% of their hp per hit for each basic ability that they have on cooldown.

I Said, Shut Up!:
After being hit by silence, if the target casts a basic ability within 1 second, Anduin automatically basic attacks them, and his basic attack timer does not reset.

Harvest Energy:
Anduin heals x health for each target hit by his basic attacks when they are enhanced by Voidform.

Clairvoyance:
Enemies hit by Mindblast deal 20% less damage to Anduin for 1.5 seconds.

Soul Shield:
Spirit Lash also gives Anduin shields equal to 100% of the health it restores to him. The shield begins to decay rapidly after 6 seconds.

Shared Agony:
If Anduin basic attacks a target who was hit by Mindblast in the last 10 seconds, all other targets who have been hit by Mindblast in the last 10 seconds also take damage from Anduin's basic attack.

Mind Lash:
While enemy Heroes are afflicted by Spirit Lash, their basic ability cooldowns recharge 75% slower.

Respectful Silence:
Hitting a target with Silence causes them to their next two basic attacks to deal x less damage.

Mental Assault:
After casting Mindblast, the next Voidform enhanced basic attack has its damage increased by 50%, and it stuns the target for 0.25 seconds.

Spirit Echoes:
After casting Spirit Lash, the next Voidform enhanced basic attack has its radius increased to 3 units and it heals Anduin for 50% of the damage dealt to heroes.

Quiet Place:
After casting Silence, the next Voidform enhanced basic attack leaves behind a 2 unit radius cloud that silences any heroes within it.

Lots of numbers are xs because I don't feel confident balancing them. Tuning the numbers I did give was hard, especially cause I was wary to give silence too much strength with its 3 second cooldown. For clarity, channeled abilites includes the cast time of abilites like pyroblast, and the clones created by Vivid Nightmare heal themselves rather than Anduin. That ult was also hard to balance, as while it can effectively double his output of damage I didnt want to make them to fragile to be useful. I think psychic scream is a bit underpowered but to me its hard to tell when there are no other abilites that interact with cooldowns. For talents, at 3 7 and 16 i wanted to try to make, instead of builds focusing on one ability, builds focusing on different themes, with each ability getting a talent that improves Anduin's basic attacks, counters enemy basic attackers, and deals with cooldowns or basic abilities. Anduin's basic attacks are ranged, with a normal ranged, and he attacks once per second for much higher than average mage damage. I wanted to make him reliant on resets with his trait for burst, like how he played in Hearthstone when raza was around. If you have anything to say about the concept, including solid numbers for abilites and talents, let me know in the comments.