CHAPTER TWENTY-THREE: Sparring Matches; Monsters, Abre And Ache.
Monsters are beings born from an aggregation of mana in one place. Most monsters are not intelligent. They usually gather into groups based on their outside appearance.
When killed, the mana that makes up their bodies gets crystallized. This crystallized mana is known as a monster core. If you are lucky, and there is excess mana after the core creation, the mana may create a random item for you. Different types of monsters have different items they usually leave behind.
Monsters would leave their natural habitat in groups in search of food when they outgrow their food source in number. The Xerxi on Planet Ko and the other intelligent beings call this a monster outbreak.
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Abre was born to a poor farmers' household in a village in the Sairitz domain of the country of Delle.