Mazoku (魔族, lit. "ma" (demon/devil) and "zoku" (race/tribe/group) is a species in Kyou Kara Maou that is born with magical powers. They are closet what is known as "Demons" in English. The Mazoku look completely human aside from their unusual beauty and long lives.
The Other World
Mazoku in the other world are much older than they appear. It is said that are 5 times the age they look. Half-Mazoku age differently, there is a chance they will age the same as humans or that they will grow in spurts or possibly even age like a mazoku. Many half mazoku children age like a normal human until around age 12 and then seem to stop aging for long periods of time.
Maryoku (magical ability) is an a trait mazoku have that allows them to use Majutsu (magic). Mazoku must make a pact with an elemental power in order to use Majutsu. The elements are earth, water, air, and fire. Most mazoku only make a pact with one element but there are a few, such as Günter, who make pacts with all of the elements. There is also healing Majutsu which seems to be innate and does not require a pact.
In human territories, where humans worship god the elements that obey them are few, they are unable to use their powers. When a mazoku is exposed to Houseki, their bodies will become weak and they will not be able to use their magic.
- Main article: Shin Makoku#Government
It's stated that both female and male Mazoku can get pregnant, give birth and even breastfeeding, although this is not fully explained. In Chapter 36, Wolfram first assumes that Yuuri has given birth to Greta when she claimed to be his illegitimate daughter instead of conceive her. In Chapter 38, while traveling to Conanshia, a ship worker thought that Wolfram had morning sickness after he told him Yuuri was his fiancé. In reality, he just had sea sickness. In Chapter 50, Conrart thinks Wolfram was giving birth when Yuuri and him were trapped with the yet unborn Bearbees. Wolfram explains that he wasn't the one giving birth because Yuuri "hasn't done anything".
Later, Celi complains to Wolfram that she was getting old and wanted to have grandkids, with Wolfram saying once again that it was not his fault as Yuuri doesn't want to "do it", that is to say, having intercouse.
Earth Mazoku are very similar to humans. Unlike the Mazoku in the other world they do not have exceptionally longer lives or magical powers. Earth mazoku have fairly normal human lives though some live well into their one hundreds.
In the anime there are exceptions to this rule though. In episode 42, Bob used magic to protect the Shibuya brothers and in one episode Wolfram (while possessed by Shinou) helps Shouri make a pact with the elements.