Asriel can't kill a conceptual, multiversal constant.
Though onto the other subject.
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UF is the conceptual embodiment of the concept of destruction of an infinite number of universe, it's attack violent power, is the embodiment of destruction, in otherwords, a conceptually attack, there is no reason to be believe he can't conceptually erase another 2-A."
Not remotely how this works. Being able to destroy a concept throughout a multiverse proves you can do just that. It doesn't prove you can destroy the concept of another 2-A, unless that 2-A is literally just a
sentient multiverse and not really anything else. Especially when there are varying degrees of 2-A. Does being able to remove the concept from one universe mean you can now conceptually erase other Low 2-Cs on your level without suggestion or proof? No, nt at all.
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So the conceptual embodiment of destruction of an infinite number of universes, can't conceptual erase another 2-A character?"
Being a conceptual 2-A character means you are a conceptual 2-A character. Without evidence, it does not mean you can conceptually destroy other 2-As.
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Also we can play this feats game if you want, show me feats of asriel affecting a conceptual entity on the scale of UF."
He can't. Though that's not the point.
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If we go by this logic neither can affect the other, which is ridiculous."
Nope, it just means "UF can't conceptually erase another 2-A without proof". It doesn't mean he can't smack up Asriel in any other way.
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This is like saying arceus can't affect 2-C's on his level cause he has never fought 2-C's on his level, yea he stomped 2-C's but not 2-C's on his exact level so it doesn't count, he has no feats of affecting 2-C's on his level, so he can't affect 2-C's on his level."
It's more akin to saying "Arceus can't instantly conceptually erase 2-C's on his level because he's never done so to 2-C's on his exact level", which is 100% true. Though going by the Creation Trio, he probably could to 2-C's a bit below his level.
If UF has conceptually destroyed other 2-As, this argument is meaningless. If he hasn't and hasn't been stated to be able to, then you need evidence to say he can. There isn't some sort of weird double standard here.