Who... [ now there's an important question to ask. ] Who and how many.

If we believe what he said about this being the first time that he's teleported people is the truth then the spells would be from people of his home.

[ ...but then would that mean he exhausted all of his resources at home for this goal of his? what could be this demanding? ]

Could these loops also be tied to what he's trying to accomplish? Not simply in the means to gather "resources" but for him to attempt whatever he is trying to accomplish without having to deal with his failures.