"I want to help you...but I can't believe in you." — Underswap!Sans talking to X-Event!Chara Underswap!Sans is a supporting character in Underverse. He hails from the Underswap universe. Although Sans intended to start unpacking and live out in the surface, he soon faced intervention from outside forces that ultimately leaves him homeless. He is eventually killed by XGaster, with his code stored in the quarantined Underswap.