Humans「人間, NIngen」in the world of Tensei Shitara Slime Datta Ken are different from the human in our world.
Humans all have some sort of affinity to magic. Some humans are capable to becoming immortal like other stronger races, in the sense that they can undergo the process of reincarnation and end up living for a thousand years, whether that's being reborn as a different person or the same.
Abilities and Personality
Human are considered to be quite smart and industrious creatures. They build cities and countries and have large highly organized groups. However, they are known for lying and treachery and caution needs to be had around them as they can easily manipulate those that cannot lie.
Humans are also very emotional being and their decisions can often be controlled more by emotion than by logic.
- Fleshy Body - Humans are bound to their fleshy body and damage to their body directly affects them, unlike Majins whose body can be quickly regenerated and simply house their energy form. If the body dies, the human will also die.
- Magic Energy - Human are able to control and channel magic energy.
- Soul - Humans have very strong and powerful souls, unlike monsters whose souls contain much less energy. Human souls can be used by demons/devils to strengthen themselves and thus are considered quite valuable by those demons that can utilize their energy.
- Nucleic Heart - Typically the Nucleic Heart will follow the soul and provide additional energy to the demon who consumes the soul. However, in special cases, the Nucleic Heart can be separated and escape or at least retain itself while the body and soul are being controlled.
Types of Humans
There are various types of humans from various origins in this world.
- Inhabitants - They are the standard Humans that are born and raised in this world. This category is not just applied to 'Humans' but actually all beings born and raised in the world.
- Reincarnates - Two types: those who were originally born in the world and those who came from another. The former are those that have died and been reborn in this world. Most of the time they are reborn as humans and can retain their memories of their past lives. In Rimuru's case, he was reborn in the body of a slime. They can be granted gifts and skills depending on their hearts' greatest desires upon their time of dying in the previous world. The latter would be those who transmigrated without being summoned.
- Transmigrates (World Travelers, Otherworlders)- Two types: those who were simply transported or reborn into this world, and those who have been summoned. The former can come to exist after dying in their previous world, or due to some kind of dimensional distortion.
- Summoned - These are Humans that have been summoned into this world from other worlds. They have the memories and the bodies they had in their previous lives but are bound to a contract to their summoners. Inhabitants can also be summoned, but they aren't Humans e.g. Demons, Spirits, etc.
These four types can also exist as intersection sets i.e. Reincarnated Inhabitants or Summoned World Travelers etc.
Humans can evolve like monsters as they get stronger though their rankings are a bit different.
Humans first strengthen themselves through training and can raise their own strength from very low to an A rank with enough training and good equipment. Examples of those are the knights and mages of the church who have gotten strong through many battles and training. There are also those humans that can gain a unique skill that adds to their ranking and fighting strength.
There begin actual evolutionary changes once their strength reaches a certain level. Evolution is as follows:
Humans are also the only species to be able to become Heroes, which is an existence meant to repel Demon Lords. Such a Title, unlike those such nobles and aristocrats, is granted by the Voice of the World to those who are worthy. Their bodies are reconstructed to have a longer lifespan and are incredibly powerful.