Doesn't Weltal operate on magic? I forget Xenogears law slightly, but I'm pretty sure it does.
No. Spoilers for Xenogears below.
Weltall is a gigantic channel for the power of the Zohar Modifier, a worldwide generator of infinite energy that entraps the Wave Existence and empowers every fancy thing you see in the game. Ether attacks? Zohar. Gears except the Xenogear? Zohar. Bosses? Zohar. You can call it 'magic' for simplicity but Xenogears is completely sci-fi. None of the ether attacks would cease to work due to their origin, and neither would Weltall. The only discussion is if Weltall retains 'Id mode' when not piloted by Id, but even the base Weltall Fei Fong Wong uses, and which other people have managed to pilot, is something Ryu just can't defeat. ---