This is a world in its most infantile state. Nothing more than a core.
It's small, and likely wouldn't be able to sustain a world like this forever, but it should work fine until Shaigis returns from the past. Or catches up to the present.
And, should she decide to make this arrangement permanent.... well I do happen to know of another world with a failing core that could use a replacement. A strong and spirited replacement.
*she grins and drops the orb, it falls to the ground with almost a water droplet sound. Though it never impacts the ground, and instead keeps going down through it. Leaving no hole, only a slight golden shine where it entered.*
There, that should keep things sane here. And, honestly, if I were Shaigis I'd let that be this world's core for good. Watching this place is enough to make me question if intelligent life really is a good idea.