Ok, this is my 1st Guide, don't know if you will enjoy it, but I've been playin with it for a while and it proved to be a nice build, especially to be easy to play with.

Well, this is supposed to be a very offensive Nocturne, thats why I've selected a 21/0/9, I don't think I have to comment the offensive points, it's standart I guess, but the utility points MUST be foccused on mana because this build requires a lot those blue thing lol.

It also explains also the Seal of Intellect, so in the early game you'll be able to do more attacks with the Duskbrienger, great to kill minions, pursuit heroes and fear them.
The runes of Desolation, no comments.
Focus it's an interestin choice because, well, in the pursuit it's always nice to have skills i believe, specially the Unspeakeble Horror.

Spells, Exhaust, good for pursuit as well as running away, I think it's a smart choice because helped me many times at 1st blood, with the Ignite toguether sometimes ( no comments about Ignite).

Now the most important I guess, the Skill Sequente.
You see, Duskbrienger it's good for all the objectives, specially in my case, a long ranged attack that makes you faster? It helps, A LOT.

Shroud of Darkness, the less important, at least in the early game for me, use it just to have more speed attack and some defense in emergency cause.

Unspeakable Horror, see, the great thing about this skill it's fear, so no need to make it lvl 5 so soon, lvl 1 has fear, so lvl 1 it's fine until you achieve lvl 5 in Duskbrienger.

Paranoia... a gorgeous Ult, lvl 3 as soon as possible!

The boots are good to try the 1st blood, or escaping it, lol.(Ionian because of the cooldown effect).
Nocturne don't have too many health obvsiouly, so you will need to recover life once in a while, but you have the duskbrienger and your passive skill (read it, really...) so I guess Nocturne will be fine, as long as you don't play as a kamikaze guy, remember, YOU ARE NOT A TANK!

Brutalizer it's kind of cheap and it haves a cooldown effect as well, good choice.

I know Bloodthirster it's a bit expensive, but believe me, if you are not the feeder of your team, you will be able to get it with no problems.

Zeal it's just the bridge to the phanton dancer, but it would take too long I guess, and Nocturne requires attack, so speed it's just for creeping and stuff.

Infinity Edge, expensive, but a really awesome iten, one of my favorites by the way, who wouldn't like to have that attack with that critical attack bonus? Essencial.

I'm not used to do the Black Cleaver, the game mus have ended sometimes, but gives some bonuses that I like, a good iten, but not your priority.

See, I will tell how I play, it works for me, if doesen't works for you, try other guide.

I usually like to take mid, reach lvl 6 as fast as I can and then start the best of Nocturne, Ganking.

Yes, Nocturne is awesome for doing that job, usually I go to top or bot when there is a enemy hero almost dead, usually near the turret trying to go back to base ( so sad for him, lol).

You just need to use your ult, do a basic Ignite and he will probably die, but if you are not sure, use Exhaust and than Ignite.
If that it's not enough for you, attack with duskbrienger and he will be more than dead for sure...

If he doesen't die and you did all that I wrote in here, you are not doing it right, REALLY...

Killing Minions it's not a hard task for Nocturne, just use your Duskbrienger in a way you will hit the most minions and do your attack on them ( in the mid ), you will kill more minions, recover some health and, the best part, win gold and recover some HP.
õ/

Yep, thats it.
If you do what I tell, you will probably do a good match, if you play it perfectly, you will get feed and make the other team surrender. ( Yeah, with most of the heroes, but with Nocturne it's waaaay cooler *__* )
Hope you enjoy this awesome Hero and this guide, if you don't, you are a noob, for sure.

Good Game for ya õ/