In That Time I Got Reincarnated As A Slime, everyday salaryman Satoru Mikami dies on the streets of Tokyo and reincarnated as a slime monster in a wild fantasy world. He takes a new name, Rimuru Tempest, and sets about creating a home for himself and his fellow monsters.
Rimuru possesses many qualities that make him a great friend and leader. He is strong, talented, and loyal, and his subordinates are genuinely devoted to him. At the same time, he has a number of weaknesses that prevent him from reaching his full potential.
Weakness: He's Hopelessly Naive
Competent leaders are expected to make the right decisions to protect their friends and subordinates. Leaders who are too trusting or short-sighted risk putting their subordinates and even their entire country at risk, so leaders must work to become wise and perceptive.
Rimuru is still a young leader and lacks the experience that is crucial in diplomatic relations with other countries. King Gazel Dwargo of the Armed Nation of Dwargon warns Rimuru that he is too soft and that he needs to act more kingly. His naivety is put on full display when he misjudges the humans of the Kingdom of Falmuth, which allows them to launch a surprise attack against him and his allies.
Strength: He Doesn't Underestimate His Opponents
Although Rimuru is naive when it comes to diplomatic relations and politics, he is very cautious and does not pick fights that he doesn't think he can win. Rather than underestimate his opponents, Rimuru has a tendency to overestimate their strength, which prevents him from being cocky in fights.
When Rimuru helps the Goblins protect their village against the invading Direwolves, Rimuru has the Goblins make preparations for the attack by setting traps and erecting barricades. Even though he was likely powerful enough to take out all of the Direwolves by himself, Rimuru did not take his opponent lightly. His hesitancy, while unnecessary, ensured an easy victory and allowed him to quickly end the fight.
Weakness: He's Overly Sentimental
Rimuru deeply loves his companions and subordinates, so much so that he is willing to put himself in harm's way to protect them. At the same time, his sentimentality can lead him to overreact when his friends are in danger and to keep promises that are hard for him to keep.
Rimuru promises Shizue before she dies that he will look out for the Otherworlder children in her care. While noble, this promise leads him to neglect his duties as a leader and allows Falmuth to attack the Jura Tempest Federation while he is away. Additionally, Rimuru is willing to sacrifice thousands of Falmuth soldiers to bring back the lives of his subordinates that are lost in their surprise attack. Those soldiers may have been his enemy, but were also largely innocent of blame.
Strength: His Predator Skill
Rimuru is extremely strong and is capable in both hand-to-hand combat and with magic. However, the most dangerous skill that he has in his arsenal is his Predator skill. Predator allows him to consume his opponent and take their unique skills as his own, making it his ultimate trump card.
In his battle with the Orc Disaster Geld, Rimuru uses Predator to consume Geld and defeat the Demon Lord Seed before he can grow more powerful. In addition to its uses in combat, Predator can also be used to store items, such as health potions, which Rimuru distributes to his injured companions. Its uses are practically endless and provide Rimuru with numerous options to approach every situation.
Weakness: He's Extremely Anxious
Despite his incredible strength and winning countless victories, Rimuru isn't very confident in his abilities. He constantly doubts himself, and gets easily flustered, especially when he is asked to act in a manner befitting of a leader.
Whenever Rimuru has to give a speech he sweats profusely and gets so nervous that he doesn't know what to say. He's hesitant to appear foolish and to make mistakes in front of his subordinates, which can cause him to doubt himself and be too passive. His fear of doing the wrong thing can lead him to do nothing at all, and this hesitancy may one day have dire consequences.
Strength: His Cunning & Decision-Making
Although he is sometimes hesitant to act, when Rimuru does make a decision it is usually the right one. He is a shrewd tactician, and he's very perceptive. He rarely makes the same mistake twice and deliberates thoughtfully before making a decision to ensure that he has not overlooked any information.
In his fight with Hinata Sakaguchi, Rimuru cleverly evades her Disintegration attack then tricks her into thinking that he was destroyed. Later, his strategy to defeat the Knights of the Western Holy Church and Falmuth is flawlessly executed, underscoring that when he puts his mind to it he can be a competent battlefield general and tactician.
Weakness: He Lacks Leadership Experience
Rimuru's naivety is exacerbated by his lack of leadership experience. His motivation to create a nation for monsters is prompted by his desire to create a home for creatures like himself and not out of a desire to amass political power. He is unused to having to make decisions for others, and this can lead him to become anxious and doubt himself.
During his diplomatic visit to the Armed Nation of Dwargon, Rimuru is unable to keep Shion in line, and she ends up acting like a fool in front of King Gazel Dwargo. His inability to control his subordinates highlights his hesitancy to take control of a situation, which is something that comes with experience.
Strength: His Loyalty To His Comrades
One of Rimuru's greatest strengths is his loyalty to his friends. He is unwilling to put his friends in harm's way unless there is a very good reason, and he is willing to die to protect them.
Before he is reincarnated, Satoru sacrifices himself to protect his friend and junior from an attacker on the street without thought for his own safety. Once he is reincarnated, he immediately befriends Veldora Storm Dragon, one of the most terrifying monsters in the world. He keeps his promise to house Veldora until he can live outside his body, and Rimuru even provides for Veldora by creating a clone for Veldora to inhabit. His word is his bond, which is one of the reasons his subordinates love him so much.
Weakness: He's Too Hard On Himself
Despite his many accomplishments and skill, Rimuru is very hard on himself. Whenever he fails to live up to his expectations or one of his companions is harmed his first instinct is to blame himself. While his ability to take responsibility is admirable, he also holds himself to impossible standards.
When he learns that Shion and hundreds of other Tempest citizens are killed in the attack by Falmuth, Rimuru blames himself rather than Falmuth because he was not there to protect his subordinates. His self-loathing motivates him to find a way to revive his companions, so it ultimately leads to a positive outcome. Still, his mental state became so distressed that he became willing to do whatever it takes to save his friends, even if that means killing thousands to become a Demon Lord.
Strength: His Great Sage Skill
Rimuru's most useful ability is his Great Sage skill. Great Sage acts as an internal computer that informs Rimuru of his different abilities and about details of the world he now calls home.
When Rimuru is reincarnated, Great Sage helps him navigate Veldora's dungeon and master the skills that he gets from traversing obstacles and defeating various monsters. During difficult fights, Rimuru relies on Great Sage's computing capacity to help him come up with an effective strategy. Now that Great Sage has evolved into Wise King Raphael, its power will be even greater than before, and there's no telling what new information he will uncover with the help of this skill.