Hi, the investigation part is tight, thanks to Tobbit’s shrewdness. But I am left with one question: why does Sigwin invest so much in the child? I think maybe there’s something alien about fae thinking that makes an oath more important than many things. But hasn’t Sigwin other things to do than claim old debts?
I based this off old fairy stories like Rumplestilskin and Changeling legends. Fae have always been interested in obtaining people's children for unknown reasons. Perhaps having a mortal child is seen as a valuable link to the mortal world or a tool for future trickery. Maybe it's just in vogue for fae to have mortal pets. But they definitely are bound to follow through with any deal they have made. They are ruled by traditions and rules. Many Fairy stories have fae making bargains and then using the language of the bargain or technicalities to trick the mortal. Fae have little else to do that is more important than tricking mortals. at least that's the impression I get from folklore