The isekai anime genre was a staple of the 2010s, and a number of the best isekai series are getting new seasons in the early 2020s, too. One of them is That Time I Got Reincarnated As A Slime, which sets itself with its optimistic tone and themes of diversity, tolerance, and building a nation out of nothing.
The hero is the aforementioned slime, Rimuru Tempest, who entered this world after getting stabbed to death in the streets of Tokyo. But Rimuru is no ordinary blob of blue jelly; he's loaded with powers and abilities, and he uses these to defeat the forces of evil and build up his benign new nation, the Jura Forest Alliance. Now, which ten of his abilities from the anime's first season are the most impressive and useful?
10 Book Creation
Rimuru Tempest can do just about anything and take on any foe, but that doesn't mean he's willing to go on a rampage. Instead, he's a creative and benign creature looking to make the world a better place by any means.
He can even act as a one-man printing firm, and, once he eats enough paper, he can churn out thousands of books, ready to read. For the most part, he chooses to print Shonen Jump and related magazines. Nothing like boosting the local literacy rates.
9 Shapeshifting
Rimuru Tempest's real body is that of a simple slime, a round blob of blue jelly that inches around the place. Slimes are normally boring, low-level monsters... except this one! He can use Predator (more on that later) and assume the form of anything that he's eaten.
This allows him to roughly assume Shizue's form, and he can even morph into a dragon, a wolf, and other creatures. If need be, he can perform partial transformations, too, and combine body parts from different creatures. Now that's flexible.
8 Magic Sense
This ability doesn't look like much from the outside, but it is very useful indeed. This new world is rife with magic, and not only can Rimuru use it himself, but he can sense it just about anywhere.
With this ability, Rimuru can detect not only the presence and nature of nearby magic, but also create an accurate mental image of what the item emitting that magic energy looks like. This ability even allows Rimuru to understand languages that he's never heard before.
7 Self-Regeneration
Just look at that soft and stretchy slime body. It is no surprise that slimes are able to regenerate their bodies when hurt, and Rimuru can do this, too. But, of course, he takes it to the next level.
Rimuru, when fighting, can restore any lost body part, and, with powers as formidable as his, this makes him nigh-undefeatable in combat. He even learns evolved forms of regeneration later on, allowing him to reconstitute himself even faster and restore lost clothing.
6 Analyze
This is a critical part of Rimuru Tempest's collection of abilities, and it functions something like a computer. Rimuru can gather data on just about anything or anyone, and a voice will tell him all the details he needs to know.
With this, Rimuru can comprehend and absorb new magic and abilities and figure out how to defeat his opponents as mercilessly or bloodlessly as he chooses. He can slay anyone in combat, but many enemies become friends after Rimuru disables them without doing serious harm. Analyze can help with that.
5 Telepathy
Here is another ability that doesn't look like much from the outside, but it is essential for Rimuru's growing circle of friends and associates. How does a slime talk? Normally, they don't... but Rimuru has the power of telepathy!
This is vital for communicating while in slime form, and he can use it to send orders or warnings to any friends and allies within a certain radius. Who needs cell phones when you can project your words into someone's brain like that?
4 Water Blade
Now it's time to discuss Rimuru's many combat abilities, and, with them, he can take down nearly anyone with minimal effort and defend his growing kingdom. It's a good thing he's a force for good, as he's nigh-unstoppable.
One of the earliest moves he learns is the water blade. He pressurizes water to an extreme degree and releases blasts of it that can slice nearly anything apart, even giant centipede monsters. Rimuru learns stronger techniques later, but this one is a fine starter move.
3 Sticky Steel Thread
This is another early technique, and it can be used in all sorts of ways. Rimuru can conjure spider webs that are hard and sharp like steel, and, in some cases, he uses them to trap an opponent as though they're a fly... and leave them vulnerable to a follow-up attack, like water blade.
But he can also use these steel webs to block off an enemy's escape route, secure his allies' escape, or capture someone without hurting him, as he did on Shion—before she got that name and became Rimuru's ally. Shion is one of the best girls in this anime, after all. We're really glad Rimuru captured her without much trouble.
2 Dark Thunder
This ability is devastating, and Rimuru performed a live-fire demonstration of it to try and scare the ogres into submission. By combining the power to control particles and dark lightning, Rimuru creates an even more potent version of the basic lightning skill.
True, the dark flame power is also fearsome, but dark thunder can be controlled quite finely, and lighting is co0ler to look at, anyway. For all we know, an even further upgraded version lays in the future!
1 Predator
This is the ability that makes many of Rimuru's other powers possible, so, naturally, it takes the top spot. How can Rimuru use so many different combat techniques and morph into other creatures? That's easy: he analyzes them after eating them!
Rimuru devours one creature after another to build up an entire library of abilities, and he can even create magic potions with the plants and minerals that he's devoured. He's a hungry little slime, and the world is a much better place for it.