It’s a really hard match for akuma. 1 genei-jin can equal 50% dmg against akuma easily if done correctly, even more off of the standing forward!
But here are some akuma strategies that I’ve played against that annoy me:
Safe air-fireballs, especially after a knockdown without a techroll: jump in air-fireball mix up high or low into demon flip kick, kara-throw, overhead, or even cancel into a farther flip and go for the flip-throw. Yun doesn’t have a solid answer to the demon flip everytime so abuse it (ex dragon kick gets stuffed a lot of times easily)
Don’t do roundhouse hurricane kicks, yun is short and if u do a RH hurricane kick I can stand up and parry the last 2 hits or keep ducking and parry the last 2 hits when the hurricane kick crosses me up from behind and that 1 mistake = genei jin. A yun player can do this with ease and a little practice everytime.
Learn the distance of the demon flip, you can stand fierce canceled into roundhouse demon flip and press the kick to cancel it very close to the ground. Many times this will actually cross up yun/yang and land behind them when it would look like it would land in front of them! This is virtually undetectable. Remember demon flip has many different scenarios depending on strength of the kick and the move u are canceling it from. I.E. close standing medium kick into medium kick demon flip is the perfect distance for the flip-throw, however if u do close standing fierce into medium kick demon flip you land a little shallow to be able to throw them from the flip. Akuma is also able to let the flip go without being canceled which makes a low hit, cancel early to mess with parrying, cancel late to fool the opponent into blocking low because they think u arent going to cancel and are going for the sweep, or cancel at a specific time close to the ground where akuma just “lands” as if from a normal jump. Make sure to use all of your options.
Akuma is a shoto and still has all of the very good shoto ticks. Crouching roundhouse is great against yun when u sweep with the tip of ur toe. Yun can’t punish the sweep if it’s far away enough with lp dash punch. So abuse that, the only counter he has for a far away cr roundhouse is ex shoulder, but that wastes genei jin meter. Knowing your distance is key.
Finally learn how to punish a parried dive kick, many times a parried dive kick to the shin/foot of a character is unpunishable by a throw and can lead to a mistake if the akuma player is not expierenced vs yun. So if u parry a deep dive kick do standing fierce, canceled into demon flip or something like that. Also if u parry a dive kick high u can cr forward into super because its a low attack which a falling character can’t block after being parried if timed right. Against yun players that like to whiff lk dive kicks in front of u so attempt to throw but then get hit by the jab short strong combo you can do standing strong or fierce, usually this will hit the yun player on his decent.
Remember the key to a akuma vs yun match is patience and playing very safe. Akuma still deals out a lot of dmg and yun’s defense is low so choosing when to throw out your attacks is key to winning.