When Zenitsu Becomes an Uchiha

[Uchiha Zenitsu: After Lightning Fried My Broom Head, I Chased My Senju Senior Brother to Propose]

As the Uchiha clan's once-in-a-century good-for-nothing, Zenitsu spent every day wailing, "I want to get married!" until the entire clan couldn't stand him. Then a bolt of lightning struck him and blew his hair into a golden broom, ruining any chance of finding a match within the clan!

Just when he was despairing, he discovered that his senior brother Kaigaku, the demon he had killed with his own hands in his previous life, had been reborn into the Senju clan. Even the grandfather he loved most had become a little old Senju man!

While Uchiha and Senju were fighting to the death on the battlefield...

Zenitsu tore off his clan crest, slipped through the barrier, and broke into the Senju bathhouse at night. With Kaigaku's Lightning Release cutting loose, he frantically proposed: "Senior Brother, marry me! I'll spend this life making it up to you with my own life!"

Senju Tobirama was so furious that he invented a sealing technique specifically for tying up Uchiha. "That blond pervert snuck into Second Brother's bed again!"

Madara crushed the new clan rules. "Expel him from the Uchiha this instant!"

Izuna's Sharingan flared with bloodshot eyes. "Why did you blow up my family's ancestral shrine while chasing Kaigaku?!"

Kaigaku chopped until his blade was blunted. "You've been harassing me for two lifetimes! What kind of karmic curse are you supposed to be?!"

#What do the clans' blood feuds have to do with my love-addled brain# #The Uchiha clan's hereditary tsundere streak destroyed by a pervert in pursuit of love# #The reason the Senju and Uchiha reconciled spread throughout the shinobi world##The rumors keep growing wilder#

A little what-if: Just a possible extra, and probably won't be written.

After the village had finally been founded, Kaigaku was hit by a strange jutsu and gave birth to a child who looked just like him. But to Senju Tobirama, the child looked more and more like an Uchiha. Most importantly, the kid looked just like his second brother as a child, except for his blond hair, which made everyone picture a certain scoundrel. By the Sage of Six Paths, of course the kid in his family wasn't an evil Uchiha.

Theme: Sincere feelings are the only way to win true love.