Yes and? Even if the destruction was caused by the creation of a phase the effect is still the smashing of other all phases. Like I said it's semantics, the end result is something being destroyed not created.
No. This is just layering the new phase on top of the old phase. They are still there and quietly exist. It is like the Thor systems, there is the new Thor who is the god of thunder and lightning, and there is the old Thor who is the god of agriculture. The new system exists on top of the old system, but the old system still exists.
No? The Hidden World phase just has special properties unlike other phases.
(The raw version said that the Hidden World and the Material World were separated by a wall, and Aleister Crowley made a hole in that wall, which caused the Hidden World and the Material World to begin to merge, so that the Magical Gods had to divide their infinite power into infinity, but I don't have the raw version, so don't believe me on that point.)
Also True Magic Gods don't need to use phase creation to destroy the world, unless you think they create phases by moving an arm or leg.
Same with the nerfed Magic Gods, other than Nepthys (who already used up her phase creation ability against Kamisato) all of them don't have the ability to create phases anymore, yet they can still destroy the world. Which is the universe+phases.
So unless their wrong about their own abilities. Their ability to destroy the world is not something to do with phase creation
I've already written that the true magic gods can destroy the universe with their infinite power, so why repeat it?
Also Othinus needing to create phases to destroy is just Touma's speculation.
By what we see she performs and says in the novel it doesn't seem like she actually needs to create phases to destroy.
He speculates that she's creating a phase when she uses Gungnir. But that's never actually confirmed and again the narrative points out that the difference is semantics cause creating a destroyed castle and destroying a castle leads to the same effect, a destroyed castle.
And again Othinus says that she can destroy and remake everything, but that creating phases is easier.
With how Gungnir is described it's more likely that what happened was simply Othinus breaking all the phases and combining the fragments into a spear.
Similarly it's also never said that Othinus created a phase to perform the destruction at the beginning of the novel so it's more likely she simply shattered everything with Gungnir.
It's never said that the black world was created by Othinus either. It's simply what Othinus and Touma saw after the destruction of the universe and all phases.
And with how NT10 explains that the hidden world phase is explicitly a thin membraneous layer at the bottom of the world that Othinus couldn't destroy...
It's more likely that the black world is the surface of the hidden world and Othinus didn't create it, it simply was uncovered after every other thing was destroyed and Othinus and Touma simply assumed it was the 'end' of the world.
As explained in the NT 10 epilogue.
Touma's words are the only explanation in the show, we have no other. And Touma's words Phases not destroying are confirmed when Othinus throws the spear, where the narration practically quotes Touma's words that it is destruction by creation. And the Black World is simply the state of the world when it is destroyed. Destroying the Phases is not easy, Coronzon needed an entire ceremony to destroy all the Phases along with the foundation, and Aleister Crowley's plan to destroy all the Phases is is compared with Fiamma's ceremony, which affected all four worlds. If destroying the Phases were so easy, Aleister Crowley wouldn't have had to summon Aiwass or anything like that. P.s. It's 2 a.m, so I'll answer you later
“Have you ever heard of phases?”
“…?”
“This world was not pure and untouched to begin with. Christian, Buddhist, Celtic, Indian, Shinto, Incan, Aztec, Greek, Roman…and Norse. The various religions have placed layer after layer of various phases over the world like thin veils or filters. There is heaven, hell, the underworld, the Pure Land, Yomi, the abyss, Mount Olympus, the fairy island, Nirai Kanai, Asgard, and many others. At any rate, the world you have seen so far has been viewed through various colors of cellophane.”
“You haven’t destroyed any of those colored glasses.”
As his vision wavered and he was unsure who he was speaking to, Kamijou managed to keep his mouth moving.
“When it comes down to it, you are a person who creates. It may be filled with malice and it may be similar to representing ‘crushing a house’ as ‘creating a pile of rubble’, but it does not change what you are. You are a person who creates.”