Board Thread:General Discussion/@comment-26680716-20160501054031/@comment-26242189-20160510002302

I think it's both their themes. You see, Megalomania has 2 meanings:

1. Psychiatry. a symptom of mental illness marked by delusions of greatness, wealth, etc. 2. an obsession with doing extravagant or grand things. Chara is number 1. They want to be great by murdering everyone. Sans is number 2. He wants to do something extravagent, despite not being able to: He wants to stop YOU.