7th Demon Prince Jilbagias' Chronicle of Demon Kingdom Toppling - Chapter 78.1 - Conversation And Atonement

The ill-fated high school student Liu Yuan obtained the inheritance of the top civilization in the universe and changed his own destiny. He also used many powerful technologies in the inheritance to lead the Chinese nation to rise in the universe.

- Description from novelbuddy

An elder asked a young man if he wanted revenge for being humiliated by a strong man and disregarded by his master. The elder offers to pass his power to the young man, who is amazed to find centuries' worth of skill appear on his phone. The power is from the Heavenly Court, where users can borrow without interest for 30 days. The young man worries it might be a 'magic loan,' but the elder assures him that it is safe, as the daily interest is very low.Zhang Yu snorted coldly and closed the ad.

A 20 year old young chef, Kai, loved Supernatural things. He loved to read and know about myths and stories and longed for them.

One day, after closing a restaurant, a voice called out inside his head.

[Help me!]

What he didn’t know was his life would change when he met a girl, a Phoenix, who asked for his help. From her, he found out about his special constitution of being able to make a contract with Mythical Beasts.

With the power of Mythical Beasts in his hand, he would shake the hidden Supernatural World.

Accompany his journey, from being a simple cook to the Mythical Slayer accompanied by a few Mythical Beasts (Girls)!

[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.