Obsidian Destroyer

An obsidian construct brought to life through the ill conceived necromancy of the Lich King, Harbinger craves magic to make up for the emptiness brought on by the incomplete nature of its summoning. Ironically however, to devour the magic that it so desires, Harbinger must tap into his own pool of mana time and time again, expending to the point where it ends up with even less than it began with. Yet despite this, the Obsidian Destroyer is a proud servant of the Undead Scourge, and takes great pleasure in annihilating the foolish Sentinels it encounters through psionic exploitation.

HERO ABILITIES (Attack range of 450)
1.)Arcane Orb - Gives the Destroyer extra power to damage his enemies based on his remaining mana pool. Damage type is pure.
2.)Astral Imprisonment - Teleports a target allied or enemy hero into an astral prison. The hero remains separated from the real world for the duration of the spell. If cast on an enemy, Harbinger steals intelligence from the target. Intelligence is restored to the hero after 60 seconds.
3.)Essence Aura - Whenever a nearby allied hero casts a spell, it has a chance to restore a portion of its mana pool. Passively adds to the Destroyer's base mana pool.
4.)Sanity's Eclipse - The Obsidian Destroyer unleashes his full potential; his mind unleashes a psionic storm able to penetrate lesser minds with terminal force, dealing massive damage to them. More crafty minds are able to resist most of the damage, but they expend most of their energies to do so, losing 75% of their mana. Heroes with more intelligence than the Destroyer are unaffected.

Are you an experienced player with Harbinger? Please leave comments below for anything you can share about items build, skills combo, strategy, etc. Thanks!