Yuusha Party ni Kawaii Ko ga Ita no de, Kokuhaku Shite Mita

Youki reincarnated on a different planet. However, rather than reincarnating as the hero or the demon lord, he was merely reincarnated as a Demon Lord's minion. The Hero's Party made an attack on the Demon Lord's castle one day with the intention of defeating him. Youki, of course, easily repelled their assault. Despite this, he ended up falling in love with Cecilia, a priest, on first sight! This is a hugely successful love comedy fantasy set in another world!