From MangaHelpers:

This manga is based on the cell-phone rpg of the same name. Two children, Kiriru and Ignato, are born to a life of fighting. Their mother hopes that they will not end up having to fight alone. As a teenager, Kiriru does not like his assigned destiny, but he must fight monsters or many other people will die. Will he accept his fate, and will he ever find a partner? [tethysdust]