Oh, I remember seeing this on Danbooru a while ago. Glad to see it made it here - it's a pretty wholesome story, and it's nice to see Tewi being mature and serious here.
Also, interesting note on dugongs - while there aren't any populations living in the waters of the main Japanese islands, there is a very small population living near Okinawa in the Ryukyu islands. Considering how old Tewi is, she probably traveled and visited the islands back when the dugong populations were larger and more widespread.
