Hello Summoners! Vayne, the Night Hunter, is a ranged assassin/carry.
This build allows Vayne to do the most damage possible throughout early, mid, and late game, while still providing amazing survivability throughout the whole game. It seams impossible, but yes, this build DOES achieve all of those things if you play Vayne correctly.
This build was generated from a complex simulation program that I wrote. It uses powerful algorithms, and considers a large amount of possible situations in order to generate the most efficient build for specific Champions.

NOTE: Vayne requires skill, spacing experience, and practice. Her two main abilities aren't simply "click and nuke." They are very versatile, powerful, and require technique and skill to use them effectively. But fear not!! This guide will hopefully teach you how to do that.

Night Hunter

(Innate): Vayne gains 40 Movement Speed when moving towards an enemy champion.
This is obviously useful for chasing down an opponent, but it does NOT apply while running away from an enemy. This (with your Ultimate) will get you so many kills at the end of team fights that it's not even fair.

Tumble

(Active): Vayne quickly tumbles a short distance, in the direction of the mouse. Her next auto-attack deals 55%/60%/65%/70%/75% bonus attack damage.
Cooldown: 6/5/4/3/2 seconds
Cost: 35 mana
This is Vayne's best ability. Use it frequently for harassing a lane, for killing, chasing, and running from enemies. Also, it's extremely important to learn how to use this to dodge the enemy's skill shots. Caitlyn usually destroys Vayne in mid lane, but if you can use this to dodge her Q (Piltover Peacemaker), you will destroy her. Note that you cannot Tumble through walls or obstacles (but you CAN pass through minions). You can use this to help escape too, but don't rely on it because you can't use it again until you auto-attack (meaning, you can't repeatedly Tumble without attacking an enemy between each Tumble). If you are not good with Tumble, you are not good with Vayne.

Silver Bolts

(Passive): The third consecutive attack or ability against the same target will deal additional damage (30/40/50/60/70) plus a percentage of the target's maximum health as bonus true damage (4%/5%/6%/7%/8%). (Max damage vs. monsters is capped at 200)
When Vayne was released, this ability was automatically claimed as "super OP OMG game-breaking." In reality, it's just some extra damage. In fact, it will almost always do less damage than a basic AP nuke. Unless you have 2.5 Attack Speed, you won't be hitting the enemy very many times in a row. If the enemy has 2000 HP, you do an extra 160 True Damage every 3 hits. Regardless, it is still very useful, especially against tanks late game.

Condemn

(Active): Vayne fires a huge bolt at her target, dealing physical damage (60/100/140/180/220 +0.5 per bonus attack damage) and knocking them back. If they collide with terrain, they are impaled, dealing bonus damage (60/100/140/180/220 +0.5 per bonus attack damage) and stunning them for 1.5 seconds.
Cooldown: 20/18/16/14/12 seconds
Cost: 90 mana
It has a hefty mana cost, but it can easily get kills if you knock the enemy into a wall. The damage is fantastic and the stun duration is fantastic. Against experienced players, it requires A LOT of skill, practice, and precision to hit an enemy into a wall. It's much easier to use in the Jungle, but a nice Tumble or Flash can position you correctly to use this almost anywhere. Note that you can hit an enemy into a Turret or Inhibitor to stun them too. The knockback effect can be used to help your escapes, but it doesn't help when more than 1 enemy is chasing you.

Final Hour (Ultimate)

(Active): Vayne gains increased attack damage (35/55/75), 1.5 second stealth during Tumble, and quadruple the bonus movement speed from Night Hunter.
Cooldown: 70 seconds
Cost: 80 mana
Duration: 8/10/12 seconds
A very nice Ultimate; this ability will get you many kills. It's almost impossible for an enemy to run away when you use this, and if they try to fight back, you'll most likely do more damage. Probably the best thing about this ability is the stealth during Tumble. If an enemy tries to fight back, you can Tumble all around them, and he'll only be able to fight back during the short time between each Tumble. The Stealth can also cause the enemy to fight poorly because they are lost in confusion, because he won't know where you are most of the time! This is especially abusive while fighting in the Brush. The low cooldown is also very nice.

First Priority: Final Hour (Ulti)
Second: Tumble (Q)
Third: Silver Bolts (W)
Fourth: Condemn (E)

If you're ganking in the Jungle before the laning phase, it's better to get Condemn first.

If you are in a Side Lane and the enemies are playing aggressively or pushing hard, get Condemn at level 2, and Silver Bolts at level 4 instead.

Flash is a NECESSITY for Vayne. If you don't use Flash, you won't be as good as a Vayne that does use it. The reson for this is that she is extremely squishy, and she needs an escape when she is targeted in team fights so she can safely re-enter the fight behind your teammates. Vayne Tank doesn't work... trust me :)

HIGHLY HIGHLY HIGHLY Recommended:
Flash

Very Good:
Teleport
Cleanse

Viable:
Clairvoyance (only if you're doing Ranked and nobody else takes it)
Ghost


Not Recommended:
Clarity
Rally
Ignite (it's your laning partner's job to get this, if they are a durable champion)
Exhaust (especially good against another Vayne or melee champions without dashes)


Very Bad for Vayne:
Revive
Smite (She's not a good Jungler)
Fortify
Heal

Personally, I use:
Flash + Cleanse
So I can escape literally any situation, and then re-enter the fight from a safe distance and angle. Vayne does so much damage that Exhaust and Ignite aren't necessarily.

I look at my options and decided which one I would rather do:

• Insta-kill one enemy with Ignite, then using Exhaust on the enemy's AD Carry, and then getting stunned/slowed and dying and becoming useless for the rest of the fight
• Survive a Team Fight and do LOADS of damage throughout the fight

I choose the second option, and you should too if you want your team to win.

I recommend 14/0/16.
It's very important to get the 6 Armor Penetration since Vayne doesn't do any magic damage.
Also, the 3% Movement Speed is extremely important since she only has a 305 base Movement Speed, and it's a waste for her to get Boots of Swiftness.
For those two reasons, this Mastery Build is the best one.

You can do 9/0/21 for the reduced Spell Cooldown and Ability Cooldown, but I don't recommend it as much.
You'd be missing out on 4 Armor Penetration and 2 Attack Damage, which is important for harassing/controlling the lane like a mofo.

Quintessences: Armor Penetration (Greater Quintessence of Desolation) OR use Movement Speed (Greater Quintessence of Swiftness) against heavy melee teams
Marks: Armor Penetration (Greater Mark of Desolation)
Seals: Flat Armor (Greater Seal of Resilience) OR Health per Level (Greater Seal of Vitality)
Glyphs: Flat Magic Resist (Greater Glyph of Warding)

This build hits for UNBELIEVABLE amounts of damage Late game, while still doing great damage during Early and Mid game. You shouldn't need survivability items until late game, because of Flash and Cleanse.

Early Game:
First off, get a Doran's Blade
If the enemy is heavy AD, get Ninja Tabi. Likewise, if they're heavy AP/CC, get Mercury's Treads.
If the enemy team is balanced between AP and AD, get Berserker's Greaves.
Then buy 2 more Doran's Blades


Mid Game:
Go straight for Infinity Edge, starting from B.F. Sword.
After that, build Phantom Dancer starting from Zeal.


Late Game:
The Late Game part of the build varies each game. Here I will explain the different situations.

First, you should already have this:
Upgraded Boots + Infinity Edge + Phantom Dancer + Doran's Blade + Doran's Blade + Doran's Blade

Fourth Item...
Do you have a good tank that can keep enemies off you, OR are you fed?
- Get a second Phantom Dancer.
Are you already pushing the enemies' base a lot?
- Get an Executioner's Calling for lasting presence in the lane.
Does the enemy team have mostly squishy Champions, but they do very high damage?
- Get a Warmog's Armor so you don't melt instantly.

Fifth Item...
After you get 1 of those items, get a Warmog's Armor.
If you already got one, get a second Phantom Dancer instead.

Sixth Item...
For your last item, get one of these, depending on the situation:
Do you kill most of the enemies very quickly, but they do the same to you?
- Get a Frozen Mallet.
Are the enemies are very tanky and you have trouble killing them fast enough?
- Get a Last Whisper.
Do many enemies have [item=Thornmail] and it's eating you apart?
- Get an Executioner's Calling
- Or get The Bloodthirster if you have the money
Are the opponents' best damage dealers AD? Are they causing you trouble?
- Get an Atma's Implaer, but ONLY if you already have Warmog's Armor (which you should, if you followed this guide)

With a full offensive build, very late game, you should be getting critical hits every hit, for over 900 damage, with at least 1.4-1.9 Attack Speed. If you got Executioner's Calling or Frozen Mallet, you'll be hitting around 600-700 instead.

If the enemy's team has a Jax, it is usually your job to get Sword of the Divine. Get this instead of a Phantom Dancer. BUT make sure you still have at least 60% Crit Chance during end-game if you do this.

Here is a simple example of how the build usually goes:
Doran's Blade #1
Boots of Speed
Doran's Blade #2
Boots of Speed ---> Berserker's Greaves
Doran's Blade #3
B.F. Sword
Cloak of Agility
B.F. Sword + Cloak of Agility ---> Infinity Edge
Zeal
Zeal ---> Phantom Dancer
Cloak of Agility (Sell Doran's Blade)
Cloak of Agility ---> Phantom Dancer
Giant's Belt (Sell Doran's Blade)
Giant's Belt ---> Warmog's Armor
Last Whisper (Sell Doran's Blade)
GG

Laning Phase

Mid Lane:
Vayne is a great mid. She can harass the enemy to ridiculous amounts, and always get the last-hit on the minions. If the enemy has a stun/root and is really aggressive, don't bother harassing; just stay safe and farm like crazy. If they don't have a stun/root, just Tumble forward, hit the enemy, and run back behind your minions. Repeat this until you get an opening for a kill (with Final Hour or Condemn) or until the enemy is forced to recall, allowing you to gank or continue farming. As long as your teammates are calling MIA, you'll dominate the mid lane against most enemies. No matter what lane you're in, to dominate you MUST learn to dodge skill-shots with your Tumble!!! Make sure you get every last-hit on the minions (without putting yourself in danger) And don't forget to ward the mid if the enemy has a Stealth Champion. You should always have more Health % than the opponent you're laning against. And remember: FARM FARM FARM FARMFARMFARMFARMFARMFARMMMM!!!!! While each minion doesn't grant very much Gold, each group of 6 minions grants a total of about 120 Gold. A normal Champion kill gives around 250 Gold, so every 2 minion waves you can get the same amount of gold as you would've from an average Champion kill!!

Side Lane:
Similar to mid lane, you'll harass very well in a side lane too. The only difference is that you must recognize the danger of 2v1; the enemies can double-team you. Do not make dangerous moves if you teammate isn't willing to do them with you. Vayne really excels in side lanes if your teammate is Tanky DPS or someone with a stun/root/silence. Just as in the mid lane, Tumble forward, hit an enemy to harass, and run back. It's much easier to Condemn in the side lane, so use that to your advantage for getting kills. If you and your teammate are in the bushes, when an enemy enters, Tumble outside of the bushes to position yourself for Condemn, and then stun them for the kill. Remember, your teammate must stay in the bushes when you Tumble out, because you need be able to see the enemies in the bushes to use Condemn.

3v3 Bottom Lane:
(See "Side Lane", above)

3v3 Top:
Almost the same as Mid Lane in 5v5, but it's MUCH easier to use Condemn. If you see the enemy running into the Jungle below, follow them (unless you'd be running into 2v1 or 3v1) and Condemn them, because it's insanely easy to use Condemn in that Jungle. Also, it's your job to ward the Lizard. Just like Mid Lane 5v5, make sure you get every last-hit on the minions (without putting yourself in danger).

Ganking Phase

While ganking, never be in front of your tank, unless you're chasing down a fleeing enemy. You're the damage dealer, not the initiator (unless you're able to initiate with a Condemn stun). Don't be afraid to use your Final Hour during each gank, because the cooldown is so low that you'll most likely be able to use it again in your next gank. Even if you think it was over-kill, a kill is still a kill, and it's best to ensure that your team gets that kill. Be sure that you don't use Condemn while chasing an opponent, unless it will stun them. The knockback could cause them to escape! If your team is retreating and there's only one enemy effectively chasing your team, use Condemn to knock them away.

Pushing and Team Fightning Phase

At this stage in the game, you should be your team's main source of damage. That means, you do everything you can to do damage in fights, without dying or getting targeted. Always stay behind your tanks, and if you get targeted, Flash out and re-enter the fight from a safe distance. Just remember to never initiate Team Fights, and always attack when your team initiates. Without you, they wont do enough damage, and they'll all die.
Also, if your tank is low on HP and your team just destroyed a Turret or Inhibitor or something, tell your team to "b", because without a tank, you'll die way to easily. Remember to focus the enemy Squishy DPS when they're in range, even if their tank has 40% Health and is right in front of your face. Remember to use your Final Hour's Stealth to your advantage, and use it with Brush if it's convenient. An expert Vayne player can turn around entire team fights by utilizing the Stealth properly in certain situations.

If that last section was too long for you to read, here are the most important things to remember:
- Always get the last-hit on minions, especially in solo lanes
- PRACTICE AND LEARN to dodge skill-shots with Tumble (VERY IMPORTANT!!!!!!!)
- Harass the enemy. Try to keep them low on Health, but be smart about it. Don't be greedy or risky
- Never initiate your Team Fights
- Always stay behind your tanks, and use Flash to get back if the enemies target you in a Team Fight
- Don't be afraid to use your Ultimate in ganks, because your cooldown is very low
- If you're mid, use a ward for the invisible Eve, Twitch, or Shaco

Thanks for reading the guide, and good luck with Vayne! I'll see you on the Fields of Justice! =)