Hey and welcome to my Nocturne Guide for 6.17. I'm a G5 player that started playing Nocturne a while ago and I'm really enjoying the playstyle of Nocturne, so I want to share it with you. Nocturne Lovers and Haters, let me introduce you to the Nocturne Play Style, which isnt really comparable to any other assasin, maybe to Rengar.

I personally dont like armorpen in jungle runes, so I start off some attack dmg, armor, magic res and attack speed in the Quints. If you want, you can also take armorpen in quints and marks but it will really slow down your clear speed

I think there are 2 choices when it comes to keystone masteries: Thunderlords and Stormraiders.
I prefer Stormraiders because you wont lack the dmg in mid to late and its always a good choice to chase or escape. If you want to focus more on the early game you should take Thunderlords. So you have to put 18 points in the cunning tree and you should spend the other 12 in the ferocity tree. In the ferocity tree you should definitely take Fury for the Attackspeed, Feast & Vampirism for Sustain and Bounty Hunter because it won't be difficult to kill at least 3 different enemies in laning phase, which makes it already better than Oppresor.
Now we come to the cunning tree. Take Savagery for better clear, the cookies because of your mana problems, Merciless for more dmg, Dangerous Game and Precision.

You should definitely start with Hunters + 3 Cookies. Try to get Tiamant before you finish your Bloodrazor/Warrior. After that try to get enough gold to finish Hydra, or finish boots and get zeal. You can decide between Swiftness and CDR Boots. I would recommend CDR Boots because you should definitely reach 40% CDR. You got different possibilities for that:
1. Warrior + CDR Boots + Black Cleaver/Trinity/Frozen Heart
2. Warrior or CDR Boots or Spirit Visage + Essence Reaver
3. 2x 20% CDR Items (Black Cleaver/Trinity/Frozen Heart), Swiftness Boots and Bloodrazor

Take R at 6,11,16. Max out Q first, then E, then, W.
It depends on your jungle route what you skill at lvl 2. If you start blue buff, i would take e because you dont got mana problems. If you start red buff, i would take w because you dont have enough mana to use e and you will get more stuns with the passive w attackspeed from the Ancient Krug Buff

Your Q is your basic damage spell and gapcloser.
Your W is a usefull spellshield which has to be timed well.
Your E is your Crowd control, which also gives you movement speed, that turns you into a speed machine combined with the q movement speed and the stormraiders.
And finally your Ult is a really nice ganking tool and makes you able to catch enemies easily.

You can go for a level 3 gank or for the power clear, which i would recommend. Start at your toplane's side and do all your camps. After that you should try to gank as often as possible and try to dont only get kills with your ultimate, also try to get some objectives because it's on long cooldown early. Nocturne's counterganks are really nice and you can also try to counterjungle when you got a lead. If you aren't ahead i wouldnt recommend counterjungling, because your only spell to escape is your q and you cant go over walls with it. Always try to get some wards in the enemy jungle to get some catches. When u R someone u should press q before u land because the extra ad the q gives u also allows your ult to do more dmg.

Pros Cons
+Great Ultimate Ganks -Squishy
+Spellspield -Bad counterjungling
+Good chasing -Useless if behind
+Snowballs hard
+Good clear
+Can be splitpushing

If you build Nocturne a bit tankier you can be one of the initiators, if you go for the assasin build i would recommend waiting for the enemy adc splitting from his team and then ulting him.