Scarlet Descent - Chapter 41 - Demon Power Field

Protagonist travels between different anime worlds to right wrongs and uncover his reason for being along the way.

- Description from Novelupdates

[You have entered the dungeon at Gwachun Station’s 1st Exit.] When former high school student Kang Woojin finds himself returned back to Earth after being forcibly summoned to a foreign planet for 20 years, he soon finds that Earth is not the same, normal place as he once remembered it to be.

Damien reveals an ugly truth.His sister and only family, Ahara, leaves the house every midnight whilst he's asleep—a time that he soon discovers is when man-eating beasts named Rouges start hunting for prey.Unable to question her directly, he decides to investigate her and quickly figures that Ahara isn't human but rather, a vampire hero who saves them from beings like herself coming from a world she calls Gibbous—a place where entities like vampires, wizards, and beast shifters alike reside. What’s more, he also learns that the real reason behind his parents' death was the leader of the Rogues, who's rumored to have escaped after Damien’s father almost killed him.A series of fateful events lead to Damien’s long-lost power reawakening in him, and he finds himself with no choice but to return to Gibbous, a strange world where power means survival, and weakness leads to death. As such, Damien enrolls in an academy to train his newfound abilities with one thing in mind...Becoming more powerful.However, he soon discovers that the path to power is one filled with troubles and pain, and he isn’t alone in this lust for more at the academy. It’s a bloody competition against time and formidable opponents, and only those willing to sacrifice their comfort are the ones who can attain it.With a deadly foe lurking in the shadows somewhere and a strong desire to protect his sister, Damein has no choice but to fight.The only way is up, and he is going to be standing at the top of them all, ready to counter any enemy.

Years ago when she was only a young girl, Rose ran away with her two friends Alexander and Mathias, just when they were about to be branded as slaves and sold to work in a brothel. Misfortunate fell on the group as Mathias became stuck and to save them, Rose sacrificed herself to distract the brothel owner’s son Graham who hunted them.Rose made her friends promise that in exchange for her sacrifice, they would return to free her. As the years passed and Rose reunited with her friends, she learned that all promises would not be kept.Stuck in a brothel with a man who wishes to turn her into his woman, Rose starts an unexpected relationship with Zayne Hamilton, a general of another kingdom. Zayne offers to buy her from Graham and opens the way for her sacrifice to not be forgotten.