MTL - Navy Traitor, I Marry the Female Emperor To Rule the Sea - Chapter 123

After Reincarnating into Naruto World at the Warring State Era as an Uzumaki, Masahiko thought that he got a useless System. He lived for 48 years as a normal, below average Uzumaki Shinobi.

That changed when he finally knew how the system works the day of his 49th Birthday!

- Description from Novelupdates

Based on the popular Vocaloid series, by HoneyWorks, called “Kokuhoku Yokou Renshuu (Confession Rehearsal)“:

Natsuki, a third-year at Sakuragaoka High School, who holds unrequited feelings for her childhood friend, Yuu, who’s in the Film Club. However, instead of being honest about her feelings, she makes him be her confession “rehearsal” partner. Unable to say her true feelings, things start to get complicated when Miou and Akari, who are also in the Art Club, get involved! Will she ever be able to confess for real!?

Waking up, Kim Hajin finds himself in a familiar world but an unfamiliar body.

Li Pu, who has the blood of a summoned beast, originally just wanted to lie down honestly, but found that his talent as a summoner seemed a bit unusual…

- Description from novelbuddy