Here's a Hero idea:
Er'tazh, Mistress of the Void Role: Assassin/Suppressive Attacker
One of the most powerful Templars ever to walk Aiur, she joined the Nezarim when they rebeled against the psionic communal link. After Adun's failure to teach them mastery of the Khala and the destruction following, Er'tazh left her Dark Templar brethren and traveled the galaxy. She later found an ancient and hidden Xel'Naga temple which responded to her prescence. She unknowingly activated an old technology, one even the Xel'Naga were afraid of. By activating it, she sped up her evolution to a state where she had full control of the void. Er'tazh then returned to her Brethren as a new being, and with it a new name.
Spell 1: Void Rift: Slash through the fabric of reality, creating a Rift near you and near the target enemy. Rift takes 3 seconds to spawn. Any enemies near the Rift after it spawns are slowly dragged to it and are only freed when the Rift dissipates, Er'tazh moves, or Er''tazh is slain. The more enemies caught by the Rift's pull, the faster it dissipates. Er'tazh can transfer attacks through the Rift, causing damage to all enemies near the Rift, but enemies can do the same.
Spell 2: Void Slash: Attack through the Rift adjacent to Er'tazh. The Void intensifies the slash, unleashing it as a wave from the other Rift. Deals damage near Er'tazh and the Rift.
Spell 3: Invoke: Channel the energies of the Void, unleashing a barrage of Void energy at a designated area. Enemies between the area and the Rift recieves damage. Attacks from both Rifts.
Ultimate: Oblivion Clash: Force both Rifts together, dragging all enemies between them to the collision point. Deals massive damage to enemies caught by the Rifts and temporarily sets the out of phase, unable to attack or be attacked.