I don't have access to curse shadow yet (not in char builder or compendium).
Here is my first build. Although I like optimizing, the flavor is my favorite part of the class.
This build goes for 100% combat advantage, I have multiple contingencies for this. It goes for amazing damage, which I accomplish with rapiers, high [w] attacks and 19-20 crit.
It has a terrific long lasting nova that lets you use curse and sneak attack damage every round for an encounter.
Hybrid Rogue/Warlock, Halfling
Initial ability scores
Str 8; Con 11; Dex 18; Int 15; Wis 10; Cha 16
Level 11 ability scores
Str 9; Con 12; Dex 21; Int 16; Wis 11; Cha 19
Feats at lvl 11
Hybrid talent (cunning sneak)
Backstabber
Wep prof rapier
Wep focus light blade
Nimble blade
Impending victory
Defensive advantage
Paragon path: Hybrid paragon
Paragon hybrid talent: shadow walk
Paragon level 7 attack power: killers ambush
Powers at level 11
At-wills:
Eye-bite, gloaming cut
Encounters:
Paragon hybrid: Killer's ambush (rogue)
Level 1: Dazing strike (rogue)
Level 3: Otherwind stride (warlock)
Level 7: Mire the mind (warlock)
Dailies:
Level 1: Crown of stars (warlock)
Level 5: Mocking strike (rogue)
Level 9: Storm Countess's kiss (warlock)
Utilities:
Level 2: Ethereal stride (warlock)
Level 6: Chameleon (rogue)
Level 10: Accursed souls (warlock)
Equipment:
Jagged rapier +3; Magic rod +2; Shadow warlock leather armor; Amulet of protection +3; Boots of stealth (heroic); Circlet of second chances (heroic); Phylactery of action (heroic tier); Gauntlets of action (heroic tier)
Tactics:
As with any rogue, the key to damage is to have combat advantage absolutely every round. With this build pulling that off is easy. Any turn in which you move more than 3 squares, you gain concealment from the warlock class feature allowing you to stealth. If you can't pull off your stealth roll, or if your enemy has blind-sight, worry not! While your shadow warlock is active, any enemy you curse grants combat advantage thanks to your armor. The concealment against the enemy in question is not a requirement, so blind-sight is irrelevant. Finally, many of your attacks give you an immediate stealth check when you use them. You will spend most of your turns adjacent to your enemies and remain completely invisible!
Your attacks deal high damage, 4d8+5 with your standard at-will, or 5d8+10 or more with many encounters or dailies. Your crit on 19-20 for massive damage (maxing our your sneak and rapier dice) and an additional 10 ongoing.
When fighting bloodied targets, you gain +1 to hit and +2 damage, so turn invisible and go get em! Your total to hit against bloodied enemies with combat advantage is +22!
Novas:
Your best bet is to start the round hidden and adjacent to the enemy. Curse your enemy if you haven't already. Use your Mocking Strike for a healthy 5d8+10. Since it is a weapon attack against will, you only need about 3+ to hit. Your enemy now has -3 to all defenses against you for this encounter. Now use a move action to teleport away with Other-wind Stride. Thanks to your class features you gain concealment and an immediate stealth check. Spend an action point to attack with Crown of Stars for another 2d12+2d6+4 damage and gain access to a cool sustain minor attack. If your enemy is bloodied they become blind, which is great. Otherwise you will have to do without stealth, but don't forget your opponent gets -2 attack from your concealment and you gain +2 AC from combat advantage with your Defensive advantage feat.
For the rest of the encounter you can now sneak attack AND use curse damage every turn. On your next turn move up to the target and stealth. Sustain crown as a minor action to do 2d6+4 damage (no opportunity attack because you are hidden) and then use gloaming cut for another 4d8+5 allowing you to shift 3 and stealth.
For the rest of the combat your enemy gets -3 defense, you get to attack for 4d8+2d6+9, and you end every turn hidden.
Contingencies:
As mentioned before, enemies that see invis. still grant combat advantage to you if you use shadow walk and curse them, so go nuts. You can still use stealth to avoid other enemies. Note that although you are technically surrounded by shadows, enemies don't know which square you are in by RAW.
Use Storm Countess's kiss to move a troublesome enemy away from you for a round or two. If they have ranged attacks you should put some cover in between you. Dazing strike is also good for troublesome enemies.
You have two items to let you re-roll saves. Save these for stunned, blind and dazed, as your low fort makes you particularly vulnerable to these conditions.
If you become immobilized, grabbed or restrained, use a teleport power to get away and get a free stealth check.
If you cannot move on your turn, you will lose concealment at the end of your turn. Stealth after you attack, and remain hidden until your next turn using the chameleon power. In this way you need only move every second turn to remain hidden.
