About the AU
Underdecay is a world where the constant resets actually start to affect not only the characters, but HOME itself. No matter the path, kindness or violence, every reset leaves a permanent mark against the new timeline, similar to a scar that never fades.
Each reset leaves a small impression on the monsters that interact with the fallen human, the result of which becomes more and more prevalent with each new reset. The monsters are slowly becoming more aware about living the same life over and over as moments of deja vu and unexplained intuition seep into their lives. The past royal scientist took it upon himself to try to mitigate the damage caused by perpetual resets and for the most part actually succeeded but in his absence, the world slowly falls into decay.
Sans is constantly worried and anxious due to the fear he developed toward resets.
The growing anxiety and worry with each reset starts to affect his decisions and his reaction as well.
Sans has a complex about his height and absolutely hates getting reminded how small he is.
He’s scared of physical contact (due to having been killed a few times) and doesn’t talk very much except if he need to. (Like many, he bottles himself up.)
When relaxed, he’s pretty close to the Sans we all know (especially when it comes to bad puns!).
His eye change color from yellow to cyan depending on his mood.
Art & Underdecay© little-noko
Undertale© Toby Fox