World #291 has scattered archipelagos with lovely white sand and winged, clawed humanoids who hatch on the beaches in springtime. The locals haven't invented writing yet; they've got stone tools, which they use to pry clams off the beach. Volcanic island topsoil is not especially suited to agriculture and they have not invented it. As usual it takes a few hours of asking to get a complete account of the magic system: you can sacrifice knowledge in singing rituals to marginally alter your flight speed or the weather. Their language is entirely lyrical.
<What if you sacrifice a lot of knowledge, can you do more than that?> he asks, and is told you can't sacrifice more knowledge than you can sing about. If you sing really fast you could get a larger small rainstorm?
They drop a Charp and an auditorium somewhere nestled into the hillside of every populated island. The auditoriums are spacious and simple and elegant to the Elven eye (Matirin finds them too stone-y). The Charp can teach flat Arda healing and literacy and mathematics and germ theory and engineering and agriculture and give these people a shot even though there are too many worlds to give them all individual attention.
World #292 just had a nuclear war. Fuck. He puts out an advisory. He verifies there's no local magic. Space volunteers to find some angels and come up with some excuse for not summoning them on-site and send them out (in a lightleaper, that'll invisibly leap dimensions a couple times) to help with healing and radiation and clouds of debris.
Demons too, he says, they're starving and we might as well put entirely new infrastructure down -
- and touch-heals until the daeva arrive, and then heads out because the daeva are not supposed to know about blue centaur aliens.
World #293 is ice-bound and the sapients are cephalopods who live well underwater. Charps will rust, so he pops back to #292 and has Cam laminate them. He has no idea how to adapt the 'auditorium' concept to underwater, so he drops them off swimming and starts running the standard set of tests.