Hi there, my nickname is Krepyy.
I play Riven for a while now,and I can say that she is a really good champion.
I was trying to find a good build on Riven,the Exile..I found few bad builds,few better.But not the real Riven.
So,I wanted to try my own build,so i was trying alot games,with various combinations of builds...and I found one which actually works pretty fine for me.

Let's start but before we begin,i want you to know that this guide is for people who experienced this character and is for sharpening your skills.THIS GUIDE WILL NOT MAKE YOU LEARN HOW TO PLAY RIVEN FROM BASICS,but how to be better with her.

I think you are not interested in lore,so I'm not going to post it here.You can read it in game or on internet anyhow.I bet you know the abilities already,but I will try to explain what is their best usage.

Prioritize maxing Ki Burst,then Valor.Having Broken Wings at rank 1 is enough,since I use it mostly for its mobility and to stack passive,not for its damage.For damage,we have Ki Burst and critical strike damage.
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Runic Blade (Passive): Riven's abilities charge her blade, causing her to do bonus damage on her next autoattack. Riven can store up to 3 charges, but only expends one at a time.Decent passive,important is try not to over stack it, so you keep it longer.
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Broken Wings: Riven steps forward and lashes out in a series of powerful sword slashes. This ability can be activated up to 3 times in a short period,3rd hit has small knockback.This ability is mostly used to close the gap.I max this last since Ki Burst sustains damage while Broken Wings are more for getting in range.
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Ki Burst: Riven damages and stuns nearby enemies.0,75 second AoE stun,great if you can get between your enemies to get most damage,but you gotta know when you can dive to fight,otherwise,you die for nothing.
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Valor: Riven dashes forward and gains a shield for a short duration.This ability is great to counter harass,adds you mobility,which is important for Riven.Great combo with Ki Burst for quick stun.
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Blade of the Exile (Ultimate): Riven's sword reforms, giving her a percentage of her total attack damage, extended range on her damaging abilities and basic attacks and the ability to use Wind Slash once.Wind Slash is execute like Garen's ultimte,but AoE and better range...It's important to learn when to use this ability,to be most effective.

For Summoner's Rift, I recommend exhaust / ignite or flash,or ghost.
For Crystal Scar,exhaust/ghost or exhaust/ignite.
If you feel like going solo then exhaust/teleport can be just what you might be looking for.
It depends on player and his gameplay.

Marks:armor penetration
Seals:cooldown reduction
Glyphs:cooldown reduction
Quints:armor penetration,critical strike damage
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-I use in this build CDR seals and glyphs,because I think Riven lacks CDR.Atleast at early game.
-You can use various runes for her,it depends on your playstyle and your own choice.

21/9/0
Taking everything offensive for AD champion in offense,plus HP in defense.Improved flash is also good utility,of course when picked as summoner spell.I use mostly Ignite so I don't pick this mastery.

Classic:
-start with doran's blade
-boots of speed,B.F. Sword
-Cooldown or Tenacity boots,depending on team
-finish Infinity Edge
-finish Trinity Force
-Bloodthirster / Thornmail
-Atma's Impaler
-Frozen Mallet


Dominion:
-open with Prospector's Blade
-rush Ionian Boots of Lucidity
-then Infinity,Trinity Force...at this point dominion usually ends...
if not..
-Thornmail,Atma's Impaler,Frozen Mallet or Sanguine Blade can add up to your damage / survivability.

Pros:
-really disruptive opponent
-high mobility
-crowd control
-ranged execute-like ultimate
-good damage output
-beefy damage late game,she can take some damage
-Valor/Ki Burst combo can lead to devastating your opponent,especially when you have friend nearby to attack
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Cons:
-requires good managing cooldowns(that's why we have runes and boots.)
-you have to get used to her abilities and how to combine them
-bit weaker at early game
-counterable mostly by ranged or AP champs in lane,again..mostly early game
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Note:
-late game most of champs die within few hits to you alone,unless they build hardcore armor
-this would cause them to lose potential of their champ,unless someone like Malphite or Rammus
-with no benefit since players who know how to focus will clear the easiest targets first and then tank alone has not much options

-look at this one,I was afk for like 6 minutes(unfortunately),but when I started playing I opened with a triple kill on low health opponents trying to take our base
-then we pushed top and bot and holded them by their base
-my offensive gameplay with small help of opponent team (no strategy and being careless) resulted in my core dominion build and we won

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-this one was also interesting,though kinda fast
-i didn't even build trinity force
-it was very amusing,mostly because of raging of opponent team


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-this is the game i played this morning,I think it went pretty well
-and i thought that game before was fast:D well,this took like 12 minutes..
-i have bought ONLY Infinity Edge and we got like 5 bases
-after my 14 kills,they finally managed to kill me for first time,ofc 4v1 ;)

''Critical strike damage on Riven? And Trinity Force? ''
Only because some people on forums say that it is useless to go crit on her,I can assure you,that people that played against my Riven didn't like my gameplay.So, what I try to say is,that my ''build'' may be different,but it works.Many people on forums diss crit damage on Riven.Mostly because passive doesn't increase on crits.Well,I assure you,that killing someone by 1 or 2 valor/ki burst combo is fun.This build allows you to be dangerous,but beefy at once.
And about Trinity Force,well...haters gonna hate.
If you are still reading this,then I want to personally Thank you, for reading my whole guide.
I hope you found information you were looking for,if not,well...better luck next time.
Peace.