Maidens of Lorely is a worthy addition to the Haifuri name by expanding on arguably the best character in the series: Wilhemina. The main series has yet to be translated, so if you're a foreigner and your Nihongo is not particularly jouzu then this is the only manga you will be able to enjoy. Making a prequel about her makes a lot of sense; she has significant experience and command that can't really be covered easily in the main story line, kinda similar to Sinbad from Magi.
Without spoiling anything, it's really cool to see how an academy on the other side of the planet operates differently from the traditional setting we see in Japan, all with the same goal of becoming Blue Mermaids. We get some good rivals and villains, and it sets up the stage for Wilhemina joining the crew on the Harekaze pretty well. If you are a fan of the show, you might as well check it out since this is the closest thing to a Haifuri manga translation that we'll ever get.
