Spoilers Alert!
You’ve dedicated your entire life to your corporate job since graduating from college. In fact, you can’t remember the last time you’ve taken a break or spent time trying to find a boyfriend! The last thing you remember was working at a breakneck pace for 50 days straight…
Now you’re here, in front of what looks like a little girl in a simple white dress with white wings on her back. Is that a circle over her head?
Ah…you’re dead, aren’t you? So this is the infamous “overwork death (過労死, karōshi)” that you’ve heard about on the news.
Shedding tears, the angel tells you, “I want you to live your next life as happily as possible. I can help you if you have any requests.”
“Then please give me immortality and a long, slow life. Living a leisurely life on a plateau would be perfect.”
“Sure! I’ll make you a 17-year old…girl…as…we…ll…”
Opening your eyes, you find yourself lying on the grass of a hilly valley and see a village in the distance. Looking behind you, you see a small house. On its front door is a notice you don’t recognize as Japanese, but somehow still understand: the house is free to anyone who wants it! Inside, you find a full-length mirror and take a look at yourself.

You are now a teenage girl with long, flowing blond hair and blue eyes, wearing a black coat and a black pointed hat, like that of a witch. Checking your pockets, you find a small dagger and some gold coins! Time to go to the village and do some shopping!
A few minutes later, a small, translucent blue blob jumps in front of you. Hmm? Is this one of those “slimes” you’ve heard about from role-playing video games? You draw your dagger and thrust it the slime clumsily. Eventually, the slime evaporates and leaves behind a small crystal. You take it, hoping to sell it later.
At the village, Furata, you are directed to the local branch of the Adventurer’s Guild, the only place where monster spoils can be sold. There, the receptionist signs you in as a Level 1 Witch and you sell the crystal for 6 copper coins. Not bad!
Over the next 300 years, you’ve been passing time at your own pace: sleeping, farming, fighting slimes or even simply lazing about. You’ve also been using your herbal knowledge, one of your skills as a Witch, to make medicines to sell at the village. The people there even consider you to be their guardian spirit and have named you “The Witch of the Plateau”.
One day, after selling slime crystals at the Adventurer’s Guild, the receptionist asks to check your status. Evidently, she’s been curious about it for a long time! Now that you think about it, you haven’t checked it since the day you first signed in…
Placing your hand on a magic slate, your stats are shown. Your Level is now…99?!
I’ve Been Killing Slimes for 300 Years and Maxed Out My Level (スライム倒して300年、知らないうちにレベルMAXになってました, Suraimu Taoshite Sanbyaku-nen, Shiranai Uchi ni Reberu Makkusu ni Nattemashita) is a light novel series, manga and anime series written by Kisetsu Morita (森田季節, Morita Kisetsu).
After dying from a stroke at work, the 27-year old office worker Azusa Aizawa finds herself reincarnated on another world as an immortal witch. Resolved to living the lazy life, she gradually grows in power by killing slimes every day for the next 300 years. As a result, she reaches Level 99 and becomes a powerful magician whose abilities soon become the talk of the land.
Azusa is gradually approached by several unusual characters and they all get together as family. Despite wanting to continue living her lazy life at first, Azusa learns to appreciate and enjoy the company of her new family and friends.
She has also found herself befriending an elder demon, attending the wedding of a dragon, negotiating a centuries-long dispute between draconic races, freeing a trapped ghost and riding a flying whale to visit the demon king himself. Despite her lack of desire for excitement, Azusa still seems to find it!

Main Characters
Azusa Aizawa (相沢梓, Aisawa Azusa), an immortal human witch. Having once died from overwork, Azusa is rather easygoing and somewhat lazy, but she is fiercely protective of her friends and has a sentimental streak. Accidentally gathering experience and power over 300 years by killing slimes every day, she has gained super strength and powerful magic in the process. As a result, Azusa can singlehandedly defeat several dragons with her bare hands!
Laika, a 300-year old red dragon. Brave, kind and competitive, Laika believes strongly in self-improvement. Able to take on human form at will, she has many skills such as cooking, cleaning, carpentry and magic. After she hears about the legendary Witch of the Plateau, Laika challenges Azusa to a duel and is quickly overpowered. The dragon persuades Azusa to take her in as a disciple and rebuilds her house, almost doubling its size. A month later, Laika attends the wedding of her older sister along with Azusa and her friends.

Falfa, a 50-year old slime spirit and the twin “sister” of Shalsha. Over the 300 years that Azusa spent killing countless slimes, the spirits of these slimes slowly merged and eventually formed two sentient creatures in the form of young human girls. Energetic, optimistic and curious, Falfa considers Azusa to be her mother because the slimes’ deaths enabled her own existence. At first, Falfa was at odds with her sister Shalsha, who wanted to avenge the slimes’ deaths, but they both later accept Azusa as their mother. In turn, Azusa has grown very fond of her newfound “daughters”.
Shalsha, a 50-year old slime spirit and the twin “sister” of Falfa. In contrast to her sister, Shalsha is a reserved and stoic intellectual who enjoys reading in her spare time. When she first appears, Shalsha is consumed with the need to avenge the slimes’ deaths at Azusa’s hands and has trained herself in Haja magic, an offensive type of magic that is strong against a specific race or person (Azusa in her case). After being defeated by Laika with a flick of a claw, Shalsha runs out of mana, forcing her to give up on vengeance.

Halkara, a 225-year old elf apothecary and entrepreneur. Ditzy and childish, Halkara is also voluptuously beautiful. After inventing a “nutritional wine” similar to modern-day energy drinks, she set up a business to sell it until she was hunted down by the elder demon Beelzebub. Halkara took refuge with Azusa until she was found by Bub, who simply wanted to purchase more nutritional wine! After this, Halkara moves her business to Furata village and later builds a new medicine workshop at Nascoute City.
Beelzebub, a 3,000-year old elder demon. The demon kingdom’s Minister of Agriculture, she is calm, polite and professional, but is of surprisingly weak constitution. Because of this, she has grown dependent on Halkara’s nutritional wine to enable herself to maintain her busy work schedule. Bub is a very powerful magician, possibly even greater than Azusa herself, and is known as the Lord of the Flies for her ability to turn into a housefly at will.
Rosalie, a human ghost. Formerly a merchant’s daughter, she hung herself after her father sold her off at Nascoute City’s red-light district. Graceful and polite in life, Rosalie is now rude, curious and carefree. Trapped at the site of her death (now occupied by Halkara’s medicine workshop), Rosalie eventually managed to escape with help from Azusa and her friends and was accepted into their family.

Personal Thoughts
Death by overwork, from stress or deprivation, is fairly commonplace in Japan, whose culture places value on social harmony and group priorities over the individual. Unfortunately, there are bosses who abuse this notion and take advantage of it to abuse workers since complaints are usually frowned upon in Japan, where the social hierarchy is deeply respected. It’s no wonder that Azusa, a typical office girl, enjoyed living a lazy life for centuries!
The story brings a humorous touch of fantasy to a modern woman’s life and several women’s issues such as a busy work life, getting married and having children. With Azusa as the reader’s stand-in, Laika acts as the best friend, Falfa and Shalsha act as the children, Halkara acts as the ditzy colleague in need of guidance and Beelzebub acts as an older, experienced colleague. It’s almost like a family drama!

There isn’t much focus or challenge in the story since Azusa is already an overpowered magician by RPG player character standards. It’s more about Azusa coming to terms with having a new, adopted family after centuries of living alone in comfort. She seems to become more fulfilled as she learns about and helps her friends, gaining a new kind of happiness and satisfaction from loving others and being loved in return.
Moral
Caring for others can be difficult at times, but it is surprisingly rewarding in itself.