But there's something unutterably pleasant about curling up in a proper bed in pajamas and just sleeping. And then waking up and getting breakfast in those pajamas. So she does that, because immortality's a long unpleasant time if you don't enjoy the little things every now and then. Like adorable bunny slippers and soft pajamas and sleeping in.
She's midway through a fruity salad thing that counts as the standard fairy breakfast when she feels the summon. Showing up to a summon in pajamas? Eh. If they're proper summoners she bets they've seen worse, and she doesn't particularly care if they think she's unprofessional.
She puts her spoon down and accepts the summon.
"... Killing me is quite impossible for anything that does not break physics harder than the Endbringers, or something that convinces me to kill myself. There are better ways to be rid of me, including asking me to go away. If you ever get that desperate."
Blink. "That." Pause. "Thanks for telling me that? Endbringers break physics? You break physics harder than them?"
"Endbringers don't actually have internal organs. They're multi-layered, kind of onion-like. The center layer is so impossibly dense that it breaks physics. My telekinesis cannot rip that apart, or crush it in any way." Pause. "So since I had my unbreakability pretty well proven to me, I tried ripping all of the layers off of Leviathan I could, and then using myself as a bullet to hit him. I worked my way up to top speed. This was starting to work until the Simurgh showed up to ruin my fun."
"Yep. Unpleasant things are only unpleasant to a certain point. I get sleepy, but I will never pass out from exhaustion or lose too much coherency. I can get stabbed, but not very deeply and I'll heal pretty quickly. I can get hungry, but never starve - you get the idea. It's pretty convenient. I have no way of testing to see if it extends to the Simurgh's song, and will never do that because that is in the running for the worst idea of all time."
This is not how she tested it, but you could conceivably test it like that.
"Yeah. And they combine well if I'm crazy enough to use myself as a battering ram. Which I am."
"Though, to be fair, I don't do it casually. I'd much prefer to not be a battering ram at all. Just, when you're up against an Endbringer..." She shrugs. "Something something anything to kill it."
"Yeah. I mean, that's my whole—justification, here. If they break physics I might need to be a bit more notorious than I'd been expecting, though."
"Maybe so, but I'm pretty sure if any power has a shot at actually killing those monsters it's mine. Probably Scion's, too, but him we can't really talk to."
"It might, if you're as indestructible as you say, which, I'll need to see to believe, really. I mean, it's not unheard of, the Siberian's probably also on the list, but."
"Fair enough. And yeah, the Siberian's probably also on the list, but good luck convincing her to fight an Endbringer."
Sigh. "...maybe you could throw her at an Endbringer instead of serving as a human missile yourself."
"Yep. Very inconvenient, wish she were on our side. But nooo, she had to be the inconvenient kind of crazy."
Snort. "If I see an opportunity I'll try it, but just as a guess, I don't think my personality or arguments could redeem her. Bit too far gone."