I'll Live a Long Life to Dote on My Favorite Stepbrother!

I'll Live a Long Life to Dote on My Favorite Stepbrother! is a fantasy romance ONA that completed its twelve-episode run in winter 2026. The series explores a unique premise where a player finds themselves reincarnated into their own raising simulation game, but with a twist: they inhabit the body of a younger brother originally destined to die, while their favorite character has been reincarnated as their stepbrother. This setup creates tension between the player's knowledge of the game's mechanics and their new reality as a supporting character rather than the protagonist they controlled.

The story examines what happens when someone with outside knowledge of a fictional world must navigate relationships and survival within it. Rather than focusing on traditional romance routes, the narrative centers on the protagonist's determination to protect and care for their favorite character across a full lifespan. The twelve episodes deliver a complete story arc, making this an accessible entry point for viewers interested in isekai concepts with romantic undertones but prefer their fantasy narratives wrapped up neatly. The ONA format allowed for a concise, focused telling without the pacing constraints of a traditional television schedule.