Although Riot believes that Nocturne is a jungler, I prefer to use him as a 3v3 powerhouse. This is the build that I like to use on the Twisted Treeline, but it does get a few "Noc, wtf r u building noob?", which later subside as you carry your team to victory.

I chose these runes to augment Nocturne's already high attack speed, making him a very fast hitter early game. The armor penetration helps with kills on any type of champion, but shines when it comes to ripping through tanks.

I chose Manamune for Nocturne because I always found myself out of mana when I really needed it, plus it adds about an extra 50-60 damage, depending on how you are playing. Berserkers Greaves are rather obvious, as is the Bloodthirster. The Brutalizer which later becomes a Youmuu's Ghostblade, is useful not only for the attack and tank shredding capabilities, but also for the cooldown reductions, reducing your ult by 10-15 seconds. Sword of the Divine gives you an obscene amount of attack speed, an extra 100 damage every few seconds, and the ability to yet again, rip through tanks. The last item is really what you feel you need. I personally like to grab a Frozen Mallet for the slow, and the fact that I find Nocturne a bit squishy. If you want the extra bang, grab that Infinity Edge. I usually don't grab a Stark's Fervor, but if you feel like you must have it, by all means go for it!

This is my first build on Mobafire, but I hope that this build works for everyone else like it works for me!