Board Thread:General Discussion/@comment-28615841-20160601023944/@comment-27701762-20160601032106

It's certainly possible that Papyrus and Sans are related to Gaster, so it's not out of the question that they are his sons. However, the argument you provide doesn't actually provide a compelling case. I'll break apart your points and number them:

1) Gaster is a skeleton-esque entity - This part is unclear. His "skin" is white, akin to Sans's and Papyrus's bones, but that gives us very little info about what kind of monster Gaster is/was. Beyond that, what makes him specifically skeleton-esque?

2) Sans has various connections to Gaster, including using Gaster Blasters - We should add that Gaster Blasters appear to constitute part of Papyrus's special attack that he does not use. This connection is certainly important, but needs to be compared to other explanations. For instance, let's say that Sans gained this power by communicating with Gaster post-accident (i.e. through Sans's studies into time travel), and shared it with Papyrus. That basic idea would sufficiently explain the same connections. So why should we accept the claim that Sans and Papyrus are Gaster's sons against this (or some other) explanation?

3) Sans and Papyrus speak in fonts that go with their names, as does Gaster - You refer to W. D. as "Wing Dings," but this is not actually confirmed. There is certainly evidence to support this conclusion, but we need to make sure there are not any other reasonable names that could apply before asserting it.

4) "They just showed up one day" - While your version would explain events, you are begging the question here by assuming the conclusion you are trying to prove to explain evidence for that conclusion. I agree with the reading that they just showed up one day refers to them arriving in Snowdin (as opposed to just popping into existence), but that reading of the line doesn't actually get us anywhere specific.

5) Connections b/w Gaster, Brothers, & Undyne - You employ a sort of "we can surmise X" logic, but without actually justifying the claims you make. Partially due to what I want to point out later. But also because you try to overexplain what is happening. Papyrus and Sans don't actually hold any authority: their checkpoints and human hunting are a partially independent venture, particularly as a way of helping Papyrus to convince Undyne to allow him into the Royal Guard. Undyne certain uses Papyrus and Sans, yet she never makes them official members of the Guard, which is something that we would expect if there was some special connection between her and the skeletons' father. Nor is there any indication from Undyne that she knew their father and was doing a special favor for him by watching over the skeletons. Given that she basically lays bare her thoughts on Papyrus, we would expect some line here referring to what you're explaining.

6) The skeletons can alter their eyes - While true, this doesn't really prove anything, as many other characters do very similar acts (Annoying Dog, Asgore, Flowey, to name a few examples which do pretty much the exact same "eye-popping" that Papyrus does). Only Sans's ability to remove his pupils completely is unique, but it does not immediately follow that that ability is related to Gaster.

7) Entry 17 - Certainly one of the two could be Sans. But that doesn't actually get us to the conclusion you need, which is that it must be Sans. It could also be two of the Gaster Followers. It could be two characters that don't actually exist in the game. It could be Alphys and some other non-Sans character. We need more to go on than "could."

Stepping back, one of the things that your theory assumes is that whatever happened to Gaster happened fairly recently in the timeline. But is this assumption justified? We know that Asgore waited a "long time" before appointing Alphys as the new Royal Scientist, but that "long time" could be five years, it could be ten years, it could be twenty, it could even be 50-100 years. It could even theoretically have happened before the death of Chara (which is generally theorized to have taken place 100 years prior to game). What evidence is there that it happened recently enough for Sans/Papyrus to be Gaster's sons?

Really, only points 2 &3 serve as evidence for your conclusion (1 does a tiny bit, but not enough). The rest either detracts from it or requires more work to make the necessary connections.