Base Attack Notes:
Night Hunter has his standard 128
melee range. His base attack is 22 - 32 damage (+23 AGI) = 45 - 55
damage. He swings his black sword at enemies in slashing and stabbing motions.
The starting items are your run of the mill starters. STR for survivability, regen consumables, and good boots. Steamboots are chosen because of the attribute bonus as well as the fact that the third skill will give you plenty of movespeed. You could go ghostmarchers if you really wanted to go super fast, though it would be redundant if you got frostburn as well.
Midgame has some situational items and some no brainers. Abyssal Skull is an amazing item because it gives him even more lifesteal and allows you to stack the abyssal lifesteal with even more essentially giving him up to 57% lifesteal if you went lifesteal build (+16% from Skill 3 at night...only +5% during the day, +16% from abyssal, and +25% from Symbol of Rage; This is indeed ridiculous, but keep in mind that this requires 8,200 gold to pull off and that's not including boots, starting items, etc that you need to live long enough to actually get those items). Staff of the Master is a good item, gives him some very badly needed STR and INT as well as buffing his ultimate nicely. Shrunken Head is there for those times when you're fighting disable heavy teams. Your second skill will let you take out one of them at least, but in the even there are more, there's shrunken. Runed Axe is there if you want a bit more regen, some splash, or really need the mana. It could really help you farm or get some team presence going.
Lategame Items are going down different paths. I would see Charged Hammer, Demonic Breastplate, Brutalizer, Shieldbreaker, Riftshards, boots as a good route that would give huge attack speed bonuses, armor reduction, crits, armor and bash... it would be very nice on him. Boots, Abyssal Skull, Symbol of Rage, Wingbow, Demonic Breastplate, and SotM would be another nice build that would be favoring survivability. It would give huge lifesteal, evasion to stack with the miss chance of your 2nd skill, armor, a boosted ult, an armor reduction, and some very nice damage and attack speed. Frostburn would be another good item that can be used for a more hunting role and would be great paired up with SotM (so you can hunt, have another slow, have even more movespeed boost, and have unobstructed vision while hunting).