The Devil's Cage - Chapter 8: Nightfall

In the rebirth, in order to prevent the tragedy of the previous life from happening, Bai Yu decided to rush to the [Tower of God] at any cost, and face everything together with his sister!

However, Bai Yu, who was bound by the system, mutated his bloodline, and transformed into a black-scaled python seems to be developing on a completely different path from his previous life…

- Description from novelbuddy

Pinning her tall body against the hard wall, he looked into her beautiful emerald green eyes as he spoke in a deep voice, "I have two options for you," his body came closer to hers as he continued, "Be my girlfriend. Or," his lips turned into a sly smile as he whispered close to her ear, "Be my boyfriend." He even dared to wink right before her as his dark orbs glinted amusingly.

The eldest son of the assassin aristocrat Tuatha Dé.

The skill, experience, knowledge of the previous life, magic, all of which grows his power as an assassin.

Excellent assassins pass through. He was usually admired as the ideal lord, and behind it wielded a blade as an assassin aristocrat.

Vainqueur Knightsbane is your average dragon: a giant, fire-breathing lizard who loves to take naps on his golden hoard, kidnap princesses for fun, and make the life of adventurers miserable. Vainqueur's only pleasure in life is to watch his treasure get bigger, one coin at a time.

So when a would-be thief turned unwilling minion tells him about "classes," "levels," and "quests," Vainqueur wonders if maybe, just maybe, he should consider a career change.

After all, why bother hunting monsters for free when you can get paid for it?