Wizards: Begin Liver Experience with Knight Breathing - Chapter 4: Advanced Breathing Method (seeking follow-up)

He was the crown prince of the shadow realm and the lord of wrath, Azrael. All creatures, demons, mortals, even angels feared him. However, everything changed after he went for a secret mission in the mortal realm in order to expand his seven sins power.Hiding his identity among the mortals, the vampires were attracted by his royal blood. The mortals were either jealous or admired his abilities. The angels were curious about him. The demons wanted to kill him and take over his power.Little did he know, he had another hidden power sealed inside of him. Something terrifying that could turn him either into the ruler of the three realms or an evil that could destroy all beings.--------------Tags: Mature Content , Comedy , Tentacles, Monster Girls , Yandere , Succubus , Magic , Demons , Angels , Hybrid , Hiding Identity, Goddess , Devil , Battle Academy , Beasts , Action , Mystery , Overpowered , Strong to Stronger , Harem , System , Servants , Handsome Male Lead , Smart Male Lead and a little bit of Slice of Life.

Cao Xin, a young man on earth, died in a car accident, traveled to a troubled world where supplies were scarce, and obtained a “Bronze Immortal Gate”…

…

- Description from novelbuddy

The spiritual energy recovers, others practice, and Xu Bai upgrades.

After getting the game system, because I haven’t received the main mission, I frantically spent 22 years of experience points.

Then……

Xu Bai suddenly discovered that he was already invincible.

Practice exercises.

Full skill.

Everyone: “Why don’t you have a bottleneck.”

Xu Bai spread his hands: “What’s the bottleneck, click to upgrade, isn’t it enough?”

- Description from novelbuddy

agreed. He thought they might just talk, have a few drinks, and that nothing significant would happen. However, she invited him to a hotel, and they spent the night together.The next morning, she told him it was just a one-night stand and that they would probably never meet again. She said goodbye and left. Ronan also decided to treat it like that.The next day, at his college's hosting club, Ronan was given the responsibility of hosting that year's annual function, where they had invited a singer.When Ronan looked up at the singer, he was shocked—it was the same woman he had spent the night with. After checking her history and social media, he formed an impression of her. Every picture she posted was in revealing clothes, bikinis, or almost nude outfits.He concluded that she was just a promiscuous woman, likely driven by lust, and that she had probably chosen to spend the night with him simply because she found him handsome.Understanding this, Ronan decided to focus on his work. That morning, she had made it clear that it was just a one-night stand and nothing more. He would treat it exactly that way and carry out his responsibilities.Protagonist has System---No NTRIt's Harem, with many girls but The Singer is Main Heroine.