Nightblade talent calculator, you can find bellow, will help you find the best build to match your playstyle as this, mostly, DPS class. Nightblade is the only class that has a vanish skill that lets you get out of sticky situation or prepare your most devastating attacks. Assassination Nightblades will be all about dealing damage (or buffing themselves to do the most damage). Shadow is the skill line you want to follow if you want to get utility abilities that will make you vanish and do the most damage while surprising your enemies. Siphoning is more about DOTs and leaching health. Great for weakening mobs while staying alive. Whether you use a bow, daggers or other means of dealing damage to your enemies, Nightblade’s skill will help you dispose of them the fastest. Pick and choose skills bellow and save them so others can see your preferred playstyle.
ESO Nightblade Skill Calculator has been updated with ESO: Morrowind PTS 3.0 data. We will be update it with new data DLC release draws closer. Be warned that this data is from the beta server and may differ from the live version. We will update it with new data at that time.
ESO Morrowind update: Nightblade Skill Calculator has been updated with 3.0.5 live server data introducing all the changes that the expansion brought. Make sure you update your builds accordingly.
Dragonknight
Sorcerer
Nightblade
Templar
WardenShadow Knight(blade)
This is a 2h Shadow Knight build, first bar for single target DPS second bar for AoE DPS. Haven't had a chance to try it in game yet, and I am not sure if it will work as it is very magicka heavy but if you can focus on getting equipment that has reduced magicka cost and max magicka it seems like it would work. Especially as the single target bar has 2 dots and you should only try and keep the heal on swallow soul up (though you can use excess magicka on it for more damage).
Idea is basically for single target using 'Dark magic' abilities to place dots on the enemy while healing yourself (I know swallow soul isn't a dot but the heal is a hot so close enough), and popping haste and/or rally when you need extra basic attack damage as your basic attacks will be a fairly decent portion of your damage.
AoE is basically toss out shades, jump in with Lotus Fan on the back most one, activate drain power, turn and twisting paths, then use cleave/weapon attacks to finish off.