Dungeon King: The Hidden Ruler - Chapter 10

Crossing into the world of Naruto, and acquiring the One Piece system, with all the powers of the world of One Piece, swordsmanship, devil fruit, domineering.

-Do you think that your fire is very powerful? I have the burning fruit.

-Do you think that your thunder is very powerful? I have a thundering fruit.

-Do you think that your otter is very powerful? I have the frozen fruit.

-Did you said you want to die? Don’t worry, I also have a nickname: Death Doctor.

- Description from Novelupdates

When Jiang Cheng was told to return to a family that he never knew or had a relationship with, he had never expected to end up meeting a young girl, and eventually, her seemingly roguish brother Gu Fei, as a first encounter in the new city.

A world where awakened individuals with special powers emerge due to a system. At the New Spring Kindergarten infant class, Gru awakens as an S-rank Hunter at the age of 4. Along with this, there is a quest assigned to her… [Quest: A child needs a strong guardian!] Why is a guardian needed? That is because Gru has no mother or father. Gru, who had no family, is adopted by the greatest Hunter in South Korea after many twists and turns, and along with that, new skills are developed… [Let’s try registering a new guardian in the slot!] [Children can earn ‘filial piety points’ through various activities, which can be used in different areas.] Gathering guardians enables faster growth? ‘That’s amazing!’ Alright, I’ll gather all the S-rank guardians!