Sindraim

Were/are the Bondsmiths charged with assigning other Knights Radiant their spren? Aside from the name's obvious implication we know that there were only 3 of them which is mostly because their spren were a lot more rare than the rest of the orders' but we also see that for example the Stormfather has dominion over lesser spren, so it would make sense for their humans to command these spren - to bond with the other Knights.