I know this has been done before (http://leagueoflegends.wikia.com/wiki/User_blog:V0ldek/Yone,_the_Death%27s_Debtor_AKA_Yasuo%27s_brother) but I wanted to do my own spin on it.
Yune is like his brother in many ways, he has high lane mobility (Less than Yasuo) and is a high risk assassin.
His Q and E interact, similarly to Yasuo.
Differences! Yune requires to kill things in order to move faster, as opposed to Yasuo who just floats around the lane. Yune’s ultimate is more useful at the end of a fight than it is at the beginning. Yune prefers 1v1 fights but can dive in to take advantage of enemies that are caught out. Yune is also better at traversing walls.
Why is Yune AP? He is AP because most of his power comes from Black Fire and his magic from the Shadow Isles. Playing his with crit chance and AD will not help as he was weak and unskilled during life. It is only through magic that he is able to kill like Yasuo can.
Yune is a custom champion in League of Legends.
Yune’'s abilities have no cost related to them and their use is limited only by cooldowns. His secondary resource bar tracks his unique mechanic: Flow.
Yune can have up to 100 Flow. Flow does not decay or generate idly. Yune generates 1 Flow with every ~25 units he travels, requiring a total of 2500 units-traveled to obtain maximum Flow. As Flow generation is based on distance traveled it is also accumulated while dashing, teleporting or when displaced by crowd control effects.
Playstyle, Laning Phase
Farm and harass, with Q and E. Dodge your opponents abilities with E and ensure your opponents lose trades with your W’s passive.
Playstyle, Mid Game
You will have to roam from the mid lane, and gank opposite or even with your ganker. You can hit enemies hard and leave them dead or out of lane. Using Ghost March and your QE combo to surpass walls, you can get to other lanes in ways that most other champions can’t.
With your ultimate you can “Equal out” the enemy ganks.
Playstyle, Late Game
Use your mobility to slide into lanes and push them, retreating back into the jungle. Once creep waves hit the tower you can blink in and use your Black Fire blade to push it down. If a champion comes to push the lane back, you can duel or harass, but always be wary of the rest of the team.
Help your team peel away with your Lotus Slash, and wait for an opportunity to single out and kill an opponent. Death may be inevitable, but try to start dueling with their burstier targets as they are more likely to trigger your ultimate and kill themselves.
With Ghost March and your Q,E combo you essentially have Flash and Ghost, making those summoner spells redundant. Barrier and Ignite are suggested as you need killing power and a way to survive your ultimate. If you want to split push even more you can grab teleport instead.
Lore is meh and subject to change..... don't read this unless you REALLY want to. Yune opened his eyes. He laid there, with his feet being battered by the tides on the shore of the Shadow Isle. Turning his head to the side, Yune saw a large man with a shovel gripping a female swordsmen, the swift by the collar. She looked at him, gripping the Gravedigger’s arm in a futile attempt to shake free of her. Her half awake struggles did not phase the Gravedigger, as he dragged her up the shore. Yune watched, unable to move except for a few minor flinches and gestures.
“Why,” He whispered, as Yorick tossed her into a hole. “Is,” Yorick pushed a pile of dirt into the pit. “This,” The Gravedigger pushed a few more lumps into the pit. “Happening?” Yorick stabbed Haynuna’s blade into the head of the grave.
The monster began walking down the beach toward Yune.
Yune spotted another sword, this one larger.
The monster paused above him before reaching for his neck.
“Yasuo!” Yune yelled, spewing black fire from his mouth.
The gravedigger paused above Yune. “Useful,” was all he uttered.