MTL - Marvel’s Disassembler - Chapter 102 Big shots (below)

A skilled but unfortunate modern-day assassin was killed in a freak accident. However, he soon found himself summoned to another world by an evil wizard, who had him possess the body of a boy as an experiment. After successfully planning the evil wizard’s downfall, he used the wizard’s body as a springboard to gain influence and power in his new world.

- Description from Novelupdates

I was a 28-year-old researcher in Japan, and before I knew it, I have been reincarnated in a fantasy world.

Furthermore, I had a half-spirit father and a spirit mother.

An aunt who is deeply attached to father, cousins who are problem children. Girls who cause awkward situations as in an otome.

Furthermore, in order to gain the affection of a love interest, a cousin even had a word battle with a king!

I am very busy helping humans as well as spirits!

And when I find people who are targeting my father,

「I’ll crush you.」

The cheat protagonist deters those who aim at her family. This is such a story.

At five years old, the child from the metaphysical family is about to leave the mountain, and the bigwigs of the capital city have come out to see him off.What's so great about a little dumpling?Yun Xiaoqi innocently spreads his hands, claiming he never intended to show off his powers; his simple wish is to be a good child while subtly dominating all sorts of spirits.Many oppose him during this time, and the “Little Celestial Maiden” Yun Ying teams up with various metaphysical leaders to continuously challenge him, only to be soundly beaten, losing face.Finally, the bigwigs bow down in reverence: it’s we mortals who were blind and offended the little ancestor!***The news of the little dumpling ruling over the metaphysical world reaches the Nether Realm.The Lord of the Nether Realm frowns: this milky little master must be the youngest and most temperamental special envoy from the Nether Realm.The little dumpling, carrying a lantern, walks among the mountains and rivers of the earth, guiding the souls with a proud stomp, declaring: Lord of the Netherworld is not much older than me, who are you calling childish!The noble and refined Lord of the Nether Realm lands and transforms into a twelve-year-old boy, gentle as jade: whatever the little envoy says is right.Yun Xiaoqi keeps waving his hands: nope, I'm just working here.

Standing before you is the Quicklime Martial Saint, the founder of the Taiyang Fist, the Flower Folding Master of Dinghu, Half-step Master Invincible Under Heaven, the First Sword of Xuanmen, the Judicial God, and Taiyi....After the end of the Dharma, a time of grand corruption descends, the world devoid of spiritual essence, and the system of Dao fruits takes precedence.Embracing Dao fruits, ascending step by step, thereby possessing the power of gods and saints, transcending the ordinary to achieve holiness.'Just like this,' Jiang Li said while summoning a dog, 'Heavenly Dog, bite him.'