Key observations about the nature of the beast.
Taken from my Tumblr; once lost, I have since figured out a way back in (...by searching my blog name in my email to figure out which alias it was attached to. So easy, and yet so elusive a solution) - it's a much more concise iteration of the extended metadata about this particular instance of W. D. Gaster.
Without further preamble • • •
Doctor W.D. Gaster: (Former) Royal Scientist; a monster that never existed. He was once a kind fellow, brimming with niceness applied to thickly to those he worked with that it sometimes came off as fake, always ready to lend a shoulder and provide emotional support to those who needed it. Curious to a fault. Played the occasional prank on his assistants just to see how they’d react, called them “behavioral studies.” Often joked that his work would be the death of him.
It was so much worse than just the death of him.
Doctor W.D. “Null” Gaster: an entity of the void (“void siren”); a quantum anomaly. A twisted corruption of what once wasn’t. Proper and polite until his curiosity gets the better of him. An emotionally manipulative eldritch abomination that plays on the vulnerabilities of his victims in order to get them to jump into the CORE and join him–after all, it would be better if they never existed. Has an interest in “the simplification of the timelines.“
❯ Quantum Anomaly: if you aren’t looking at him, he can be anywhere and nowhere all at once. Requires direct observation for a measurable presence.
❯ Void Siren: A term he created for himself, for his tendency to manipulate monsters into taking a long walk off the short pier into the CORE.
❯ Null: A second name that this Gaster has taken on in effort to differentiate himself from Gasters hailing from other timelines.
✴ Although he can take on a more coherent appearance, he tends to be a bit… Lazy about it. It takes concentration and, while it isn’t all that difficult, it is tiring. That said, his appearance is generally malleable. The only truly “solid” parts of his body are his head and his hands.
✴ The void-goop that comprises the majority of his form doesn’t really feel like anything. It doesn’t leave any traces behind on the surfaces it comes into contact with. It can act similar to slime or to smoke at any given time.
✴ His only weak spot is his head and his two main hands. If you wanna kick his ass, you’re gonna have to aim for the face.
✴ Although he can conjure a countless number of disembodied hands from seemingly nowhere, the more he has in play, the slower and more inaccurate he gets with controlling them.
✴ He’s selectively mute. For the most part he communicates through sign language or pictographs.
✴ His soul and his magic are black. He’s no longer a monster–he’s an entity of the void. His magic halves the effectiveness of other magic upon himself. It doesn’t have any offensive uses, however.
✴ It isn’t clear what kind of monster he was prior to becoming a void beast, but this Gaster was not a skeleton. As for his age, he claims to be approaching a century.
✴ He was a juvenile around the time of the war that resulted in Monsterkind’s banishment to the Underground.
✴ This Gaster’s “fall” into the CORE was a deliberate attempt to kill himself. It, quite obviously, did the opposite. Now he never existed, and what has never existed cannot die. However, he did escape the stressors that lead him to making the attempt. There’s always a silver lining.
✴ … However, he took the way the multiverse adjusted for his erasure as a personal insult. The Alphys he personally knew was an intelligent and capable woman, sure, but she was not smart enough to have created the CORE, nor capable enough to have achieved even a third of what he had, and yet she was the one to inherit his success? – A long time of brooding over this has made him despise the poor nerd. She’s usually his first and second favorite target in a new timeline.