I've Been Killing Slimes for 300 Years and Maxed Out My Level is one of the cutest new anime to watch in 2021, and it follows Azusa Aizawa's happy-go-lucky adventures with her growing family of misfits. Having died at her office desk due to overwork, Azusa is reincarnated in a fantasy world and wishes to become immortal so that she can live forever and enjoy the peace of an easygoing lifestyle.
However, her quiet life is disrupted by the various creatures that live around her, and she ends up adopting dragons, elves, and bunny girls into her makeshift family. The main cast is made up of strong female characters, who are all well-written, adorable, and in some cases extremely physically powerful.
Kuku The Rabbit Girl
Kuku the traveling minstrel, also known as Schifanoia, meaning "an escape from boredom," has no magical or physical powers, but her music has the power to touch people's hearts. Flatorte the Blue Dragon is inspired to help Kuku become more true to herself after being a fan of Schifanoia for a long time, and Kuku's performance at the Demon Festival moved everyone to tears.
Kuku is timid and would likely run from a physical fight, but, through the Aizawa family, she learns to rely on friends and become a confident person that would stand up for herself if confronted.
Shalsha And Falfa
These twin sisters are the manifestation of various slime spirits that Azusa has killed. Shalsha initially appeared in the show with a deep desire to kill Azusa in revenge for the slime spirits. However, she underestimated the ability needed to cast a certain spell and failed to harm Azusa. Shalsha is introverted, and, after becoming Azusa's daughter, doesn't seek out violence. She only knows one magic spell, Smiting Evil, so she has no range in her fighting ability.
Falfa is intelligent like her sister, but she is more outgoing and enthusiastic. Falfa has no magical abilities and actively avoids confrontation, demonstrated when she alerted Azusa to Shalsha's desire to kill her. Falfa is more practical than Shalsha and may find a way out of a conflict that doesn't involve violence.
Halkara The Elf
The anime's main source of fan service, Halkara is a businesswoman that invented a tonic called Nutri-Spirit, similar to an energy drink. She has terrible luck and often angers more powerful character. Ffor example, Halkara turned Azusa into a child version of herself by serving poisonous mushrooms at dinner. Azusa finds herself angry or frustrated with Halkara on a weekly basis.
Halkara might be able to strike down opponents entirely on accident such as headbutting Pecora into unconsciousness, but, if she tried putting effort into a fight, she would lose. Rosalie was easily able to possess her due to Halkara's weak mind and low level.
Rosalie The Ghost
Rosalie died 140 years before the events of the show and was forced to live in an empty, boring house until the Aizawa family rescued her. Rosalie has the powers of flight, invisibility, and intangibility, and she can also levitate objects to a certain extent and can possess people with low levels such as Halkara.
She relies on Azusa's help for things such as changing clothes and is not as powerful or highly leveled as other characters. Rosalie is protective of others and has a delinquent nature, so she would be passionate enough to fight anyone that threatened her family.
Flatorte The Blue Dragon
Flatorte is a powerful Blue Dragon hailing from a clan of dragons that have held a grudge against the Red Dragons for hundreds of years. In her first appearance in the show, Flatorte fights Laika and the Red Dragons, showing her physical prowess and willingness to fight. However, Flatorte is defeated by Azusa and becomes her servant despite Azusa's objections.
Flatorte is abrasive and rude to people in general and often battles Laika in competitions of cooking and physical prowess. Flatorte loses a lot of these battles but refuses to give up, and she has shown throughout the series that she is extremely tenacious. She is fired up by people expressing their passions, such as Kuku, and admires powerful people like Azusa.
Laika The Red Dragon
Laika is the first to be adopted into Azusa's family as she arrives to challenge Azusa to a fight. Laika loses the fight and becomes Azusa's apprentice, doing household chores and training to become a better fighter. Of the two main dragons in the series, Laika may be more highly leveled as she actively sought out opponents such as Azusa to become stronger, whereas Flatorte shows little evidence of having leveled up.
Laika starts as an arrogant—albeit cool—dragon and becomes much more friendly through Azusa's guidance. However, she is never one to back down from a challenge, especially as Flatorte often challenges her to mini competitions.
Vania And Fatla
These sisters are Leviathans, giant sky whales that can turn into human form. They are employed by the Demon King as transportation and used by high-ranking demons to get from place to place in style. In their whale form, they carry a hotel resort on their back and transport their guests, and, in their human form, they look after the guests in the hotel and use the facilities to relax.
As giant sky whales, these characters are naturally powerful. They escorted Azusa through the Tree of Life to cure her when Halkara turned her into a child. Vania and Fatla are basically flight attendants, taking down opponents with ease and giving useful information about their surroundings.
Provat Pecora Allieres
The King of the Demon Kingdom, Pecora, is a supremely powerful being and around 5,000 years old. She can be manipulative, teasing others to get a reaction from them, but she ensures that the Demon Kingdom stays on good terms with the human kingdoms, as there is a history of conflict between them.
However, in her first anime appearance, she is knocked out by a headbutt from Halkara and submitted to bedrest for a few days. When she awakens, she challenges Azusa to a duel and loses due to the difference in their levels. As Azusa trains a little every day to get her level to 99, Pecora does not need to fight due to her peaceful kingdom and does not encounter monsters to kill very often. So, despite her rank as King, her level is not as high as Azusa's.
Beelzebub The Demon
Beelzebub first appears in the series as a formidable demon intent on challenging Azusa and forcing Halkara to make more energy drinks. Over time, she becomes friendly with the Aizawa family and helps them when they summon her. As the Lord of the Flies, Beelzebub is extremely powerful, and, against a normal opponent, she would undoubtedly win. However, her usual opponent is Azusa.
Beelzebub challenges Azusa to duels more often than any other character, confident in her abilities and eager to fight. She has more opportunities to train than Demon King Pecora, so her level would be at least a little higher, but it's certainly not enough to match Azusa.
Azusa Aizawa
Azusa is so overpowered that she could probably beat Thanos in a fight. Azusa has beaten demon kings and dragons, but she always promotes a message of peace and unity. Her main goal is to have an easygoing life, so she only uses violence when needed and rarely seeks out a fight. She got her powers through training just a little every day for 300 years, taking the lessons she learned in her old life to heart and never letting herself overwork again.
The fun, comedic performance from Aoi Yuki makes Azusa one of the best characters in the show, and her magical prowess cements her as the strongest.