I play Nocturne as a high attack damage/crit/movement speed build. Why not AS for my passive: (Umbra Blades). First, Nocturne has 2 spells that scale off of AD, (Paranoia) and (Duskbringer), which scales greatly and gives him outrageous bursting potential. Second, (Umbra Blades) does take 10s to refresh and is reduced 1s per hit, but even at max AS your only doing 2.5 hits per second making a little before 4s the fastest to refresh the passive. What this means is every 4s in a fight your passive is used, but the issue is why do you need 4s... I can burst people down faster than that, even with straight auto attack. Last, in both ways AS or AD in 4s your only using your passive once because that is how long the one kill should take, meaning only using your passive ONCE. So its better off have amazing AD to have strong Auto attack and spells.

I cover my attack speed needs with these 3: .

I have 5 devices supporting my movement speed: (with 20 stacks), These are necessary because movement speed is Nocturne's escape, as well movement speed is excellent for chasing.

3 items supporting crit: gives Nocturne 55% crit then + 3% from mastery.

Now damage, its easy to see damage is a stat given by every item but my , so yes Nocturne hits like a truck late game.

Now survivability, yes barely any survivability because he doesn't initiate team fights, and above all this build doesn't need survivability if you do well in laning phase, then move into ganking.

Pros:
- Powerful Carry/Anti Carry
- Good 2 Second CC
- Spell Barrier
- Largest range charge ability
- Excellent mobility
- Great tower pushing and chasing
- Can Jungle/Minion Farm
- Great Late Game Champion

Cons:
- Squishy
- Not the best escape, without counting mobility
- Dying effects snowball items
- Can't cancel (Paranoia) when in progress...

(Ghost) - Makes Nocturne close gaps on about anyone, and gives you an escape.
(Exhaust) - Helps you chase, or weaken someone attacking you. Nocturne does a lot of 1v1s using (Paranoia) and this gives you a greater chance of killing their carry 1v1.
(Ignite) - I see some Nocturnes use this for a little extra damage for when they are out of attack range. It is effective early game, but late game it becomes practically useless compared to (Exhaust).
(Flash) - This could help Nocturne escape or surprise enemies, but really your (Paranoia) will close the gap.
(Smite) - Jungling

(Duskbringer) - Nuke damage and gives you increased movement speed and attack damage, great spell for chasing and escaping.
(Shroud of Darkness) - Giving a carry a spell barrior allows for amazing 1v1 fights, Makes fights with champs that have CC easy.
(Unspeakable Horror) - A great cc, this and your spell barrior makes you have amazing 1v1 potential.
(Paranoia) - The bread and butter for Nocturne. Allows him to go in focus their carries.

Greater Mark of Desolation(Greater Mark of Desolation) and Greater Quintessence of Desolation(Greater Quintessence of Desolation) - At start Nocturne will have 31 ArP from runes and masteries. ArP allow for him to do more damage to tanks, but mainly its for doing full damage to carries. Combine this with the (Youmuu's Ghostblade) to have 51 ArP, which will allow Nocturne to reduce most carries armors down to 0 late game if they have no armor defensive items.

(Greater Seal of Clarity) - Honestly this might not be the best rune for seals, but for me I hate being out of mana and going back to base. (Greater Seal of Alacrity) or Greater Seal of Vitality(Greater Seal of Vitality) could be better choices.

(Greater Glyph of Focus) - 5% CD Reduction doesn't seem like a big thing, but paired with (Youmuu's Ghostblade) gives 20% CD reduction, which is very helpful with ganking becasuse this item is an early item in the build. The CD reduction mainly helps (Paranoia). Another option is (Greater Glyph of Alacrity).

1. Pure Offensive: Great Start

2. Part Defensive: Decent/Bad Start

Build Indepth

(Boots of Swiftness) - I prefer more movement speed, but I do know (Berserker's Greaves) is great for him. It comes down to your personal preference. I'd rather have more mobility so i can cover the map easier, and now even more with this patch: v1. 0. 0. 115 nerfing Noc's (Paranoia) range reduced to 2000/2750/3500 from 2500/3250/4000, (Unspeakable Horror) Cast range reduced to 475 from 500 and leash range reduced to 550 from 600, (Duskbringer) attack damage bonus reduced to 15/25/35/45/55 from 20/30/40/50/60.

(Sword of the Occult) - A lot of Attack Damage and Movement Speed with 20 stacks.

(Youmuu's Ghostblade) - This item could be one of his most important items. Decent AD, Crit, ArP, and CD Reduction, Also Attack Speed + Movement Speed on activate. Once activated this items allows for great chasing and escaping. This item brings Nocturne's ArP up to 51.

(The Bloodthirster) - Your one life steal item, which offers a great amount of AD with minion/champion stacks.

(Infinity Edge) - Great Attack Damage and decent crit, but for any crit build this item is a must for the 50% damage bonus on your crits. In this build end game crit% is 58%.

(Trinity Force) - Not everyone considers this item, but it is good for quiet a few reasons. Good stats across the board even some HP and that last bit of crit to get over 50%. Last, my favorite thing is the 3 passives. 12% movement speed, chance to slow, and 150% increased base damage on next attack after spell. Obviously the movement speed and the slow makes you keep up with anyone, but the 150% more base damage can grant your crits to be quiet a bit higher, your range of damage from a crit is around 1500-1900. I believe my highest was a 1800 something.

(Phatom Dancer) - Gives crit and movement speed, which is the main reasons for the 2 items taken out from the main build.

(Banshee's Veil) - 2 Spell barriors to help you resist more CC with a good amount of hp.

1. Be good at guessing enemy abilities for (Shroud of Darkness)
2. Be able to aim (Duskbringer)
3. Focus enemy carries
4. Farm minions any down time you have, This build is pricey
5. Fear enemies of greatest threat...not only the person your attacking
6. (Bloodthirster) and (Sword of the Occult) are snowball items: don't die, don't be recklessly
7. You DON'T initiate, your the janitor, clean house

* Team fights (Paranoia) a range carry, being squishy and are usually in the back lines makes them a easy target, also their teammates should be locked into battle with your teammates; if you went in at the right time.
* Save your (Duskbringer) til your positive it will hit the target, because the trail gives great amounts of speed and attack damage.

These games are after patch: v1. 0. 0. 115. My items are in different order because I sometimes organize my items, and I have my last for a keybind.