There are several characters in the anime world that are incredibly powerful yet remain overshadowed by the main characters. While they may serve as mentors or important figures alongside our protagonists, these strong characters often face challenges that prevent their full potential from being realized.
Here are 7 notable characters:
1. All Might – My Hero Academia

Toshinori Yagi, also known as All Might, is not just an idealistic hero; his existence serves as an inspiration and a beacon of hope for ordinary people and other heroes alike. However, after his battle against All For One last year, All Might suffered severe injuries, making it impossible for him to maintain his heroic form for long periods. His strength continues to diminish, and after another confrontation with All For One, he can no longer use his powers.
2. Gol D. Roger – One Piece

Gol D. Roger is considered one of the strongest characters in One Piece. He was capable of matching the powerful Kozuki Oden and fought evenly against Whitebeard, who was once deemed the strongest man in the world. Unfortunately, while Whitebeard lived to be 72 and Rayleigh to 78, Roger passed away at the age of 53 due to a terminal illness. Roger was ill during his final journey to Laugh Tale, and he ultimately chose to surrender himself to the Marines, allowing the world to know the legacy of the Pirate King.
3. Kimimaro – Naruto

Kimimaro is one of the last surviving members of Kaguya’s clan and possesses the unique Shikotsumyaku bloodline limit. This power allows him to manipulate his own bones for offense and defense. Tragically, he suffers from a terminal illness that ultimately prevents him from reaching his full potential and living a long life.
4. Uchiha Itachi – Naruto
Itachi is known as one of the strongest characters in the Naruto series. Unfortunately, he suffers from a rare disease, which prevents him from living to old age. Itachi must frequently take medication to prolong his life until his brother, Sasuke, becomes strong enough to face him in battle. The disease significantly impacts Itachi’s physical capabilities, making each battle more challenging.
5. Shishio Makoto – Rurouni Kenshin
In terms of combat ability and endurance, Shishio is a formidable opponent for Kenshin. Makoto Shishio is a powerful warrior leading a group of highly skilled mercenaries. His character embodies the essence of “survival of the fittest,” as he faces challenges with overwhelming strength and cunning. However, his body is severely burned, making him reliant on special bandages to maintain his condition during battles.
6. Jushiro Ukitake – Bleach

Jushiro Ukitake is the captain of Squad 13 in Bleach. If not for Yamamoto, he and Shunsui would be the two longest-serving and strongest captains in Gotei 13. However, Ukitake suffers from a chronic illness that affects his ability to fight; prolonged battles can re-trigger his condition. This necessitates him to take frequent breaks and delegate responsibilities to his subordinates.
7. Izumi Curtis – Fullmetal Alchemist
Izumi is not only a skilled alchemist but also a strong and determined woman. In practice, she is even stronger than both of her students, Edward and Al. Despite her strength, she suffers from a serious illness that often causes her to bleed. Izumi once attempted to transmute her child to bring back her deceased son but ultimately failed, leading her to bear the weight of that loss.