Excellent mythic tale that explains why some magical creatures no longer exist amongst us.
the gods agreed to place, in large letters and in all languages, a sign on the horizon saying: "No trespassing: stay away".
This is a great interpretation of the prompt. Your descriptions of these characters are well done because they show how majestic they are, and this makes their loss even more poignant.
"Why do you think so?" -asked the mermaids, dipping their tails in the waves so foamy and fragile that they looked like cotton lace.
In line went the mermaids, the minotaurs, the centaurs and the unicorns. Also the elves, the gnomes and all those creatures who held curiosity and rebellion in their hearts.
I like this notion that this creatures disappeared because they were too rebellious, perhaps too exotic and magical to be among humans.
It was a fun tale to read. Nicely done!
Coming from you, your words touch me. I know the quality of your stories and writing. Thank you very much. Hugs