Stitches was part of a large group of healers and people of similar capabilities who had been conscripted from the same area. Since Stitches' plane was located pretty far from the border between the human and the demon realms, his hometown wasn't in any danger. But that also meant he had a long way to travel by boat.
A lot of the demons' initial attacks had been executed thanks to the widespread portals in the human realm, and until the people in charge figured out how the demons had infiltrated the portals, they would be shut down. Without portals, the only way to travel was through the Void using ships and boats. Since not everyone used or could afford to use portals, it wasn't a new means of transport, and there were a lot of void boats, but not enough for the entire army to go around.
