Hajime Saitou is loosely based on the real third-squad captain of the Shinsengumi. During the Meiji era, he lived as a police officer under the name of Gorou Fujita. In the Rurouni Kenshin series, he plays the role of Kenshin's old rival and enemy from the Bakumatsu. He has no compassion or mercy for his enemies and he lives by the Shinsengumi code "Aku Soku Zan (悪即斬)," literally "Slay Evil Immediately," but more poetically rendered as "Swift Death To Evil." His signature technique is the Gatotsu, a left-handed thrust and a variation of the Hirazuki technique developed by Toshizou Hijikata, the Vice Commander of the Shinsengumi. Although the Gatotsu is a fictional technique only found within the Rurouni Kenshin series, the Hirazuki is a real technique that was used by many of the Shinsengumi members.

The leader of Akatsuki is a mysterious figure. None of the other Akatsuki members refer to him by name, instead simply calling him "leader," and his face is rarely shown. He has the respect of most of his subordinates (Hidan is an exception) and is the one directing their actions. He is also the one to initiate and supervise the jutsu that forcibly brings a tailed beast out of its host. He can also use the Shape shifting Technique (象転の術, Shōten no Jutsu?) to clone his subordinates using human sacrifices, allowing them to engage the enemy without risking themselves. The clones formed are a perfect copy of the target, even possessing the kekkei genkai and unique weapons of the original. Their abilities are proportionate to the amount of chakra given to the clone (in its debut, the leader requested thirty percent). When it becomes necessary to gather his subordinates, he can communicate with them over long distances through some form of telepathy.

King Bradley is the Führer of the Amestris state military and has all state alchemist under his direct command. King Bradley almost always maintains a kind and calm demeanor even when issuing orders to engage in battle. In both iterations of Bradley, he is shown to be highly skilled with a saber. Despite his fairly advanced age, his arduous and extensive training since childhood has conditioned him to the absolute peak of human physical potential, granting him considerable speed, reflexes, agility, and strength well beyond the standard of his age, even compared to most men still in their prime. He also possesses remarkable stamina and resilience, able to continue fighting effectively even with critical wounds and reduced eye sight. A formidable opponent in battle, Bradley's lifelong training has given him remarkable mastery in firearms, martial arts, and has become especially known for his inhuman skill in swordsmanship, being able to wield up to five swords simultaneously and strike with blinding speed and precision. He has also demonstrated himself to be extremely intelligent and skilled in military weapons.As a Homunculus, Bradley possesses a special kind of power in his left eye, giving him sight abilities that far exceed a regular human's eyesight; allowing him to read an opponent in battle and avoid oncoming attacks with little to no effort. This ability is known as the "Ultimate Eye". Bradley later states that his aging body irritates him, as it isn't able to keep pace with the power of his Ultimate Eye, suggesting that his power is exclusive to his eyesight and that his other physical abilities are purely his own from years of extensive training.

Teresa was Claymore No.1 and the 182nd warrior of the 77th generation created by the Organization. Possessor of incredible power, she is the strongest Claymore to ever be created, and as such, she belongs to the group of eight Claymores who were considered to be stronger than the Creatures of the Abyss. Due to her enormous power, she rarely had to use Yoki, merely using ten percent in her battles against Rosemary and Priscilla.
Nicknamed "Teresa of the Faint Smile" (微笑のテレサ, Bishō no Teresa, lit. "Smiling Teresa") for the lacking of specific techniques and for the faint smiles that graced her face as she effortlessly slaughtered Yoma. Had she survived, she would be a sure threat to the remaining Abyssal Ones and to the creature who surpasses the abyssal, Priscilla.