Manga by author Miyashima

I woke up as the daughter of the grand duke in a novel- the same world as Raon, my favorite character. This must be God's grace towards me, a fan! But of all things, I'd become Istina, the very villainess who always caused Raon trouble. Raon is disgusted at the very sight of Istina. However, I persistently followed him around, hoping to become friendly with Raon. "Hey, Raon!" "I don't want to." "But I haven't even said anything yet" "I know exactly what I dislike." At first, he completely ignored me, but now, he's tolerating me at least a little, right? I'm going to continue being a fan. Come on, let's cheer up!

Dungeons began to suddenly appear throughout the worldKyomi Aki became an S-Class adventurer assassin with his tremendous speed.Unfortunately, assassins were considered as a failure class.His class was becoming harder and harder to master the more he advanced.The class itself had a low attack power and mana, so he needed to always rely on someone else.One day, Aki encountered a dangerous monster that could wipe out the entirety of humanity.He somewhat managed to subjugate the monster, but lost his life in the process.Suddenly, he awoke and found himself having regressed 20 years into the past.He also received an additional "Bonus Quest" as a reward for solo killing the monster.With his knowledge from his previous lifetime and this "quest," Aki resolved himself to redo everything to become the strongest adventurer.