I'm posting the thread from the QR code here in case the tweet ever gets deleted or the user closes their account:
the kasen "gate" thread i said i would make starts here okay so something i've never seen before by anyone mention or notice is that Kasen has a gap type portal ability analogous to Yukari's and i wanna make this thread for at least to try and show that in chapter 36 of wild and horned hermit, Kasen firstly seems to sense something and opens a gap-like opening and pulls out Yukari, note that the way she's sticking out her arm in a meaningful manner. what's important here is the details, note the look of this background on this panel, it will be vitally important later. Then note the look of this gap, its very distinct, its definitely not Yukari's because Yukari's has the ribbons at the end, and the eyes (and sometimes limbs) this gap is also an opening from the first picture from the panel prior. Again remember that panel. Now, look at the same kind of gap she uses to summon Housu, her tiger. Its the same black void now, remember back to the previous panels from chapter 36, compare that black and white void with this, its the same black desolate hell with some white star like things in the background. The Infinite Nightmare Hell, Avici touhou is a series heavily built on implications, if you don't make the connections you will miss out on alot of subtext and is part of why this series is so incredible because its full of it. Kasen is implied to be the former ruler/creator of Avici here and elsewhere we can see this with avici going from this black abyss to this battlefield of debris and skeletons, at the will of Kasen's arm. then later we can see kasen's arm pull a skeleton head out of the ground, then classifying it has the unlimited servants of hell. Then later on we are told directly all of those skeletons are of the infinite amount of people she's eaten prior to this point. if this wasn't at least her own hell she ruled then why would she have an literally infinite army of servants from the people she's eaten there, after she changed the entirety of avici to be the battlefield on which they're buried the at the early bit of chapter 50, when talking about when she got her arm cut off, you can see her in the same black and white area, with her skeletons below her. Then talking about losing interest in this, as in, her hellish reality. then after it gets cut off we can see what looks looks rain pouring down, which would imply that its doing so because she feels down and the reality she lives in mirrors how she feels. Even more slight evidence that she rules/created avici. and then going back to the gap thing, you gotta think of how kasen proper got out of avici after her arm got hacked off, especially so quickly after reimu left, who herself can just float in-between realms. Really makes you think that hmmm just maybe she can gap too. but why did at the prologue did i call her "gaps" a gate? well in chapter 48 when tenshi and komachi busted into her dojo and then her study room, they found that the oni gate was open and then... in ulil, the comiket 87 demo, Kasen had a spellcard called Tiger Sign "Housu of Both Gates" which then had her open several "gaps" just like I showed earlier and have Housu jump through them So Yukari's got gaps, Okina's got doors, Kasen's got gates. addendum: Kasen also has demonstrated the ability to instantly appear in places in some sort of instant movement, in chapter 2 she surprises sanae by talking appearing in the place a panel prior she wasn't at then in chapter 7 she again seemingly comes from nowhere then in ulil and aocf, kasen demonstrates some form of instant movement by transporting manzairaku to bounce a beachball off his nose this is further confirmed when this is directly mentioned in the chapter 30.5 bonus material notice how none of this shows her using a gate, it leaves us with the implication that her gates have some sort of other purpose besides from movement, which would be in line with Okina's doors and Yukari's gaps. now what those purposes are I can't tell you, its a secret, just like Kasen's signature ability. It's just one of many "various things" that Kasen said she could do. One more thing u think i should clear up, when i said "ruler" i dont mean absolute ruler, i mean like a manager role where yeah it's "your" place, but your superiors still can override you. I say this because we know that all of Hell is ran like a buisness. And we know that hells also is overseen by onis And at the end of chapter 49.5 the pentagram Tenshi brute forced was stated to lead to Kasen's world. I.e Avici is her world outright