"Am I missing something?"
You're not missing anything. It's just that not all races of Ashan will like it. The Demons certainly won't. We only have a specific canon in its entirety.
"1. Shio is like a prison, right? So, they are indeed being locked up. And it would be bad if a new part of the game appeared every time they broke out. A clever plan by Ubisoft.
2. Sorry, but there are no demons in the old universe. The Krigans are being subjected to genocide on a local scale because they haven't reached their home world, but they keep sending their own from there. Locking them up? No, thank you."
1. They are being locked up, yes.
2. But what if we try to lock them up - or even cause a collapse of that sector of the galaxy by colliding stars - the Ancients should be able to do that.
"Hello, prototype Isabel."
I doubt it. If she were a prototype of Isabel, then Izzy wouldn't be a fool, and at the very least, she wouldn't trust necromancers.
"It doesn't work. If YOU didn't understand the plot, that's only your problem."
Maybe it is. But I don't understand at all why they say, "until the global feud between Archibald and Roland." For me, "global" means "to raise the whole world," if you'll excuse me. At least the level of World War I.
Sincerely.
P.S. I'm going to delve deeper into the lore of the Ancients' universe.