Tales of Wedding Rings

Tales of Wedding Rings (Kekkon Yubiwa Monogatari) is an isekai fantasy romance/harem anime adaptation of the manga by Maybe.

Quick synopsis: High school student Satou (or Haruto Satou) has long harbored feelings for his beautiful childhood friend Hime (Krystal Novaty Nokanatika). When she suddenly announces she's moving away and says goodbye, he follows her through a portal to another world—only to discover she's a princess from that realm, returning to fulfill a political marriage arranged to help combat demonic threats.

Satou crashes the wedding, and during a demon attack, Hime kisses him instead of her intended groom, making him her husband. She passes her magical ring to him, granting him powerful light-based abilities as the prophesied "Ring King"—a hero destined to save the world from the Abyssal King by gathering multiple rings (and wives) from different princesses of various nations and elements.

The story follows Satou's adventures in this fantasy world as he builds a harem of princesses (each tied to a ring and unique powers), fights demons, and embraces his unexpected role as a legendary hero—while navigating romance, responsibility, and world-saving duties.

It's a classic isekai with heavy harem elements, action, and ecchi vibes.