This reflected not only characters with physical power, but also with other positive qualities like strength of spirit, dedication, and mental acuity.

Here are top 20 strongest child characters in anime/manga.

1. Aladdin from Magi. 

2. Trunks from Dragon Ball Z. 

3. Baby Beel from Beelzebub. 

4. Child Emperor from One-Punch Man. 

5. Reborn from Reborn! 

6. Wendy Marvell from Fairy Tail. 

7. Kagura from Gintama. 

8. Son Goten from Dragon Ball Z. 

9. Illyasviel von Einzbern from Fate/stay night. 

10. Son Goku from Dragon Ball. 

11. Killua Zoldyck from Hunter x Hunter. 

12. Shinnosuke Nohara from Crayon Shin-chan.

13. Sakura Kinomoto from Cardcaptor Sakura. 

14. Takeshi Goda from Doraemon. 

15. Gon Freecss from Hunter x Hunter. 

16. Satoshi / Ash from Pokémon. 

17. Conan Edogawa from Case Closed / Detective Conan. 

18. Arale Norimaki from Dr. Slump. 

19. Nanoha Takamachi from Magical Girl Lyrical Nanoha.

20. Son Gohan from Dragon Ball Z. 

(source:mangapanda)