Shameless copy paste!
Super Stats
Level 6: Intelligence (Primary)
Level 10: Constitution (Secondary)
Level 15: Dexterity (Secondary)
Talents
Level 1: The Glacier (Dex: 8, Con: 10, Int: 10, End: 10)
Level 6: Enduring (Con: 8)
Level 9: Brilliant (Int: 8)
Level 12: Agile (Dex: 8)
Level 15: Energetic (End: 8)
Level 18: Boundless Reserves (Con: 5, End: 5)
Level 21: Investigator (Int: 5, End: 5)
Powers
Level 1: Radiance
Level 1: Vengeance (Rank 2, Rank 3)
Level 6: Conviction (Rank 2, Rank 3)
Level 8: Seraphim (Rank 2, Rank 3)
Level 11: Mental Precision
or Spellcaster
Level 14: Dimensional Collapse (Glimpse of the Abyss, Lingering Darkness)
Level 17: Shadow Blast (Devoid)
Level 20: Conjuring
Level 23: Ebon Ruin (Rank 2, Nyctophobia)
Level 26: Lifedrain (Rank 2, Rank 3)
Level 29: Ebon Void (Rank 2, Rank 3)
Level 32: Illumination
Level 35: Planar Fracture (Rank 2, Rank 3)
Level 38: Rebirth
Specializations
Intelligence: Enlightened (3/3)
Intelligence: Tactician (2/2)
Intelligence: Detect Vulnerability (3/3)
Intelligence: Expertise (2/2)
Guardian: Fortified Gear (3/3)
Guardian: Ruthless (2/2)
Guardian: Find the Mark (3/3)
Guardian: The Best Defense (2/3)
Vindicator: Aggressive Stance (2/2)
Vindicator: Merciless (3/3)
Vindicator: The Rush of Battle (3/3)
Vindicator: Focused Strikes (1/3)
Vindicator: Mass Destruction (1/3)
Mastery: Intelligence Mastery (1/1)
This build would stack either Dexterity or Intelligence depending on what Form (Level 11 Power choice) you take, but for the most part, simply use Dimensional Collapse to trigger either form and keep up Devoid once applied via Shadow Blast. Ebon Ruin for your big single target damage, Vengeance for AoE. Conviction, Illuminate, and Lifedrain are all means of healing if you're taking too much damage.
I made this build when I was very tired!
Hope this helps anyway!