Hello Erhnam & Neiska,
I recommend not placing a Ghost Widow's Embrace: Chance of Damage in Demon Prince. The proc would only trigger when the Prince uses his Block of Ice power. Admittedly, the Prince uses this power quite a bit - I believe he opens with it. But your Prince would proc significantly more by slotting slow procs(aka -Speed) into him.
Summon Demon Prince
Summons forth a foul Demon Prince from the deepest reaches of the Abyss. The Demon Prince is mighty among its kind and is a master of cold powers. It serves the conjuror only so that it may wreak havoc upon the material plane. The Demon has some defense versus lethal, smashing, fire and cold attacks. You may only have 1 Demon Prince under your control at any given time. If you attempt to summon another Demon Prince the power will fail.
Recharge
Very Long
Minimum Level
26 (Mastermind)
Effects
Summon Demon Prince
Basic Powers
Ice Blast (Moderate Damage, -Recharge, -Speed)
Shiver (Cone -Recharge, -Speed)
Equip Powers
Chilling Embrace {Area -Recharge, -Speed)
Ice Sword (Moderate Damage, -Recharge, -Speed)
Block of Ice (Moderate Damage, Hold, -Recharge, -Speed)
Upgrade Powers
Ice Slash (High Damage, -Recharge, -Speed)
Frozen Aura (Area Moderate Damage, Sleep)
Enhancements
Enhance Accuracy
Enhance Damage
Reduce Endurance Cost
Enhance Hold Duration
Enhance Sleep Duration
Enhance Slow
Set Categories
Pet Damage
Holds
Sleep
Slow Movement
Since Neiska was kind enough to post a build, I put something together. Not to take advantage of +Def set bonuses, but to take advantage of +Recharge. I can safely say that any /Thermal MM would like more +Recharge.
Oh, one other thing, the Soulbound Allegiance: Chance for Build Up works fantastic in Summon Demons. Its ok in the Prince power, but really shines in Summon Demons.
bellona10 - Demon.Poison3.mxd