Most of Aster's past is unknown, but it is said that he was a prodigy, and entered the Sybak university at age nine. Sometime after this, he began to study in the research laboratories, being partnered with the half-elf Richter Abend. Despite them being of two different races, they became good friends. Two years prior to the events of the story, when the worlds of Sylvarant and Tethe'alla merged into one world, Aster's research into Summon Spirits led him to hypothesize that a Summon Spirit controlled the world's flow of mana. He and Richter set out to prove the existence of Ratatosk, the Summon Spirit in question, and hopefully convince him to take back up his duties so that the natural disasters plaguing the newly-joined world will cease.