It cost 10 gold coins, not 100.
Also the person at the end is definitely Dario, the asshole guy who's a "kamikaze swordsman" and has raked up tabs all across town and now all stores hate him.
He's prolly gonna try to extort money from Douglas. TBH like it was said before, the person originally set to do this would have been the Sage in the WN, but it would make more sense if the dickhead Dario were the one to try and piss Douglas off by kidnapping a little girl. A sage doing it felt a bit off, but infuriating nonetheless.