Okay I've been currently playing a dark elf nightblade. I've maxed out sneak and illusion and have basically been using invisibilty, pacifiy, or frenzy in my left hand and a dagger in my right. It's been an absolute blast so far. I'm just wondering what other skill I should add to the build to round it out. I'm planning on maxing out armsman so my sneaks hit as hard as possibly. I'm using the Nightingale Armor instead of the Dark Brotherhood Armor so I'm only getting the 15x damage. So hopefully with maxed armsman my damage will be enough. Any tips would be most appreciated. I few other threads I've read mentioned going into destruction. That sounds pretty cool too. Decisions, decisions...

Please help. Just wondering if what to do with this character at this point. Should go into destruction a little bit and use runes or maybe go into conjuration and use some bound weapons? Or should I just leave the build as it is and go into secondary skills like pickpocketing? Thanks again

Conjuration. While you're sneaking up enemies will be focused on them. Some of the high level summoned daedra are DEVASTATING, too.

Enchanting would give you some enormous damage addons to that dagger you're using if you're looking for instant kills. You can then also craft your own enchanted gear if you grow weary of the Nightingale Armor.