Board Thread:General Discussion/@comment-27850860-20160223031547/@comment-27850860-20160223074743

That is not what the model's proposal is. Superego and ID are just different functions that the Ego uses to make decisions. They can either be opposing to or completely fine with each other, but are inherently different in nature. It is quite fitting then that Sans and Papyrus are brothers (at least that is how it has been in my experience), yet have contrasting personalities.

Who Ego is in the Undertale-verse is the real deal-breaker in whether or not Sans & Papyrus can be seen as Superego and ID.

But this isn't really the primary focus of the theory, as I can fit Papyrus and Sans into this:

https://en.wikipedia.org/wiki/Erikson%27s_stages_of_psychosocial_development

Without having that logic matter.