Saiyan x Senran Kagura

Prologue

Ikki a elite Saiyan warrior from planet vegeta had arrived on earth and was taken in by Son Goku and trained Ikki for a long time.

He also been training his brain which made Goku wife chi chi proud.

Son Ikki has grown stronger and stronger in each battle he has participated with the Z fighters and has learned a good few number of moves from them.

Ikki had achieved Super Saiyan and pushed it beyond onto the next levels super saiyan 2, 3 and even achieved super saiyan 4 since he still had his tail and was able to control his great ape form and had taken in enough blutz waves.

He had also gotten his mystic form unlocked thanks to the Old Kai who saw great potential in Son Ikki.
Ikki even got a chance to become a Super Saiyan God and leaned how to activate the power on his own.
Then later on he still trained and leaned that he is now a uncle at the right filled age of 16.

The next two years were filled with him helping Goku and training with Vegeta and was soon taken with Whis to train with Goku and Vegeta on Lord Beerus planet and soon manage to unlock Super Saiyan blue and later on a tournament against universe 6 and 7

Son Ikki did what goku did and used the kaioken with Super Saiyan blue up to times 20.
Then they met Zeno and both he and goku became his friends.
Then Ikki helped fight against goku black and met future Trunks and fought goku black and nearly died and pushed his Super Saiyan blue to it max and ascended but still lost.
Though in the end they managed to beat Zamasu by stealing him away with the mufasa technique and Ikki remembered to take the seal.

Then they got Zeno a new friend which was future Zeno.
Next the tournament of power was announced and they all started to train real hard.

During the tournament many fought with all their might, and Ikki and Goku, they showed that they are getting what some thought as Ultra Instinct but it was partial mastered.
Then when they faced against Jiren both managed to fully master it and now they manage to beat him together with Frieza and 17s help and in the end 17 made the wish to restore the erased universes and they all went back home to relax.

Secretly Ikki managed to transform into Ultra Instinct later on.
Though this is where your story begins.