Llyr was a merman. 100 Years ago all mermaids a were banned from walking on earth, now mermaids are allowed to room freely. This immediately caused an increase in mixed couples. And Y/N in a relationship with one. It was basically just a normal relationship. Mermaids, Mermen were able to hide their form as long as they didn’t touch saltwater. Although there’s one thing that did make them different from everyone else. At the start of every spring was mating season for the species, for mermen specificity they would extremely weaken and their scales would show on the side on their face. Some other symptoms would include, sensitivity, to their lovers touch, extreme arousal, and fatigue. It would often go away after being cared for by their lover, and drinking warm salt water, this would cause them to be in their form for a while.