Leino was a Kuusaman mage during the Derlavaian War. He was married to fellow mage Pekka. His wife was a theoretical mage, involved in innovative research into the fundmantal principles of magic, while Leino was a practical mage concerned with applying well-known magical methods to achieve practical results. Both of them had academic jobs and had a harmonious marriage which produced one son, Uto. Later Ilmarinen, Pekka's fellow reseracher and friend, found out about Leino's infidelity but decided that Pekka was better off remaining ignorant of her husband's affair.