Summoned to Another World for a Second Time

Slightly gloomy teen Setsu is summoned to another world to save them, but wait, this isn't his first time doing it. Five years in the alternative world of Eclair have passed since the hero came to end the war and brought peace. However, a trap sent him back to his original world as a baby with his memories and powers intact. War's threatening the land again, but this hero is ready for round two!