There are a lot of strong Anime characters each with their own characteristic powers and abilities, these abilities give them great strength and power yet there are still characters without any such abilities but are still considered great warriors, some even in their verse. 

some of them are: 

there's no denying the fact that Suzaku was a force to behold, even without powers of geass he is still considered one of, if not the best pilot in the series. 

he can easily destroy most enemies through the use of his Lancelot. 

he does have some anger issues and an inability to commit crime therefore he is positioned low on this list. even still he is a force to behold.

Now... not many people might know about this guy, as he isn't as mainstream as the others.

quick introduction: Brawler is a criminal in the anime series known as Akudama Drive. He is considered one of the most dangerous criminals (akudama) known to have the best fighting ability amongst them due to his brute force and sheer strength.

Afro is an incredibly skilled swordsman from the anime Afro samurai. unlike most anime that depict swordsmen with some kind of ability/energy when talking about swordsmen afro samurai does it differently. 

he is technically the strongest fighter in his verse because he is ranked number two and has earned the right to challenge the number one and defeated him. 

7. Kenshin Himura 

A character from Rurouni Kenshin: Kenshin is a former assassin turned wanderer who is skilled in the sword fighting style known as Hiten Mitsurugi-Ryu. He is known for his incredible speed and precision in combat, and while he does have a special technique that allows him to temporarily boost his strength, it is not a supernatural ability.

The ever-popular Levi not just in his world but also in real life. 

Levi is the leader of the survey corps and the most skilled fighter there. don't let his height fool you he's not someone just anybody can mess around with.

he is proficient in the blade and is an expert at using his mobility gear. 

Thorfinn is a character that became strong because of his will to get revenge, he is incredibly skilled and uses a short knife and incredible savage attacks, some might even refer to him as a beast both in looks and character. 

Gintoki is the main protagonist of the Gintama series. He is the founder and president of the Yoruzuya, as well as a highly-skilled samurai, having fought in the Joui War in the past. During the war, he became known as the Shiroyasha (literally meaning "White Yaksha", a kind of demon in Buddhism and Hinduism) due to his powerful swordsmanship, demonic appearance, white clothing, and silver hair.

Despite all these qualities he doesn't possess any sort of supernatural ability in a world where super strong battle-loving aliens are present.

Guts is the main character of the anime series Berserk. he is a renowned swordsman and a mercenary, second only to Griffith in authority.

he is so powerful that no one can lift his sword talk less of using it in battle. yet he uses it with ease giving him the title of the black swordsman

this here is another example of a character who became strong due to adversaries.

The beast himself is a walking living menace to all living things. Yujiro is the father of Baki and a man with the title of the strongest living creature on earth.

this guy was able to stop an earthquake with his punch, beat someone who plays tug-of-war with helicopters, and even defeat an elephant so big that tanks couldn't damage it. and he did all this with his bare hands. this guy deserves respect, he isn't just a menace he is a walking catastrophe. 

Saitama from One Punch Man: Saitama is the main character of One Punch Man and is known for his immense strength, which he gained through intense training. Despite his incredible power, Saitama does not have any supernatural abilities, making him a strong character in a more realistic sense.