Aster is a human with ginger hair in a ponytail, a cowboy hat, and a brown poncho. He is the boyfriend of Missy, a monster, and friend to Vessel, Zak, and Haru (deceased). His arch nemesis, Shellock, harassed the party throughout their journey in the Underground, though he managed to defeat him in New Home and SPARE him. Aster has fought many monsters and SPAREd them all, except RATURE, who he and the party were forced to FIGHT. His goal is to leave the Underground with his friends.