Human Civilization is one of the participants in the Battle of Divine Will. They can be found in Divine Land's 4 picture scrolls, their representative seems to be constantly changing over the course of history. Their current location is in the southeast of the continent, behind the Impassable Mountains, and Fjord islands in the Vortex sea.
Human Civilization is divided in several societies:
- Kingdom of Graycastle
- Kingdom of Dawn
- Wolfsheart Kingdom
- Kingdom of Eternal Winter
- Sand Nation or Southernmost Region
Its total population is not precisely declared, but is smaller than the demons inside the second Deity of Gods, which seems to be around 10 million  and a lot smaller than their total numbers of 100 million people. It is known that the entire Kingdom had between two to four million people and that the population of the Kingdom of Everwinter and the Kingdom of Wolfheart was around 3 million. Also, the combined populace of Graycastle and the Kingdom of Dawn after the treaty between them is of a few million people. Moreover, it is known that before the formation of the Four Kingdoms, the human race had nearly 10 million people alive.  With all of this in mind, the human population can be estimated to be between 5 and 10 million people.
During the first Battle of Divine Will, witches and common people were collaborating to fight against demons, but the core of the fighting forces were witches with their abilities.
The Witch Federation was founded after the First Battle of Divine Will by the survivors, the Union had transformed from an unofficial alliance to a unified political entity.
Humans were led by witches alone, common people didn't hold political power.
After the First Battle of Divine Will they were reached out by the Underground Civilization, and began to slowly discover their technology.
The survivors fled to the Barbarian lands, and established themselves, creating the 4 kingdoms, fjords merchants, and the Church.
With the Witch hunt and the secrets of the Church, the humans lost their knowledge of demons, and witches regressed in their use of magic.
During the Third Battle of Divine Will, groups such as the Taquila Witches, Sleeping Spell, Witch Union, and the Kingdom of Graycastle are united to fight against demons, with Roland Wimbledon as their leader.
They are now fighting against demons in the north with the Kingdom of Wolfheart as battle line.
Humans defeated western front of Demons through Napalm bombs and Edith's military strategies.
Demons eventually used their second and final Deity of Gods, however, it was nuked by humans, twice. Over 10+ million demons, 2 demon lords and the demon king were killed, thereby leading to the defeat of demons.
Sky-sea Realm overwhelmed Humans. However, they were obliterated after Roland manages to convince Custodian (God).
Estimated Age of Civilization in Roland's World
By following the invention of firearms in Roland's World, we can deduce that it takes place around ~900 AD when converted to earth's year. Just by taking some evidence from this link [], "It may never be known with certainty who invented the first explosive, black powder, which is a mixture of saltpetre (potassium nitrate), sulfur, and charcoal (carbon). The consensus is that it originated in China in the 10th century, but that its use there was almost exclusively in fireworks and signals".
Similar in the middle ages on earth, the people of Roland's world love to link things they don't understand or comprehend to either witches or demons. This could be seen many times throughout the series. Many people seem to believe in god as well compared to the modern world. However, not everyone feels the same way as Tilly Wimbledon is a great example.
- Chapter 1453
- Chapter 1454
- Chapter 1418
- Chapter 1173
- Chapter 1434
- Chapter 987
- Chapter 1166