The World's Least Interesting Master Swordsman: Volume 8

The fourth time’s the charm! Saiga has lost three times and promised never to fight Sansui again, but with a reason to fight Sansui again, the two agree to fight in a flashy duel! Mizu Saiga is blessed with the ability to use all types of Rare Arts and has three cute fiances. It had appeared like the start of his Isekai Harem Cheat Life, but he had been brought down three times by the most simple attacks and took serious damage to his pride each time. A little effort isn’t enough to catch up to an Immortal who had trained for five hundred years. In order to fulfill the role expected of him, Saiga resolves to fight the greatest swordsman once again. Meanwhile, with his return to Arcana, Sansui receives news that Blois is giving birth!!! Hey, Papa, when are you marrying Mama Blois?

[From J-Novel Club]