But he has a really good reason.
He destroys, and he moves.
"...and the Sphere part you can't explain."
"Oh - well, I could show you," he offers, and then there is a portal shimmering in the air next to them.
"That doesn't look spherical."
"It's not, it's a portal. To my Sphere. C'mon."
He walks through it.
"You're sure this is safe?" calls Cor.
"Why would it not be safe???"
"I don't know! I'm just asking!" He follows.
They are on a balcony overlooking a stunningly gorgeous mountainside, with a forest and a wide shining lake at the bottom. Overhead, the sky is dark and full of starry lights, but between the 'stars' are streaks of swirling silver like someone went to paint the moon and got it very wrong.
"Prettiest Sphere I've ever seen," Tias says proudly. "I wonder why it's so big - they usually start out barely big enough to fit a house, and keep growing as long as you're alive."
"...which is indefinitely since you're ageless now? Wow, that's a neat sky."
"Yeah. My dad's is boring but it's huge, he's five thousand years old. And nothing in there but a flat grassy field as far as the eye can see, 'cause that's the kind of person he is, I guess."
At the rear of the balcony, a pair of ornate double doors lead into what must be a house built into the mountain. "I wonder if there's clothes in there," says Tias, opening them and going through.
"You don't just automatically know?"
"Nope! Where would be the fun in that?"
The interior of the house is richly decorated, palace-like, with wide corridors and high ceilings and comfortable-looking furniture. And, behind the third door he tries, a wardrobe. He throws on a pair of pants and doesn't bother with a shirt.
"This is all designed stuff. What designed it?"
"...me, I guess? But not me, like... a person's Sphere is their place, it's things that suit them, that they'd like and want, but you don't actually get to pick."
"Huh. Well, it's all very tasteful."
He laughs. "Thanks!"
"You're welcome! Anyway, we don't have these where I'm from and this place is too small and too pretty for any of the urgent applications even if you took it into your head to donate it, I guess I'll have to find planets how I was originally planning to after all."
"Guess so. Why not just run off and leave the whole mess behind, though?"
"...'cause a billion people, or however many are left after the war, are gonna die?"
"Well... and? Do you like any of 'em?"
"...yes, but even if I didn't..."
"Even if you didn't...?"
"...then I still wouldn't want a billion people to die?"
Tias seems to find this very puzzling for some reason!
"...are you from a place where it is customary to be indifferent to large death tolls?"