I can't really blame people being taken by Mandreis - especially after everything that went on in that side-story, and that personality! In the main story I liked Mandra's sassiness and daring nature next to the MC, and the clear bitterness they hold towards Mathias for all their older brother's pampering and naivety - the flaws and complexity in this character made them fun to get to know, and I wanted to learn more. However, it was during the newest side-story that Mandra truly captured my heart, to the point where I knew my MC would probably go as far as forsaking his precious knightly vows (in at least one playthrough, if possible), just so he could give Mandra all the love and care they'd never had for all those years. Corny af? Yes - but every word the truth. xD
I also wanted to say, it doesn't take much to recognize the care you put into creating these characters and the story surrounding them, nor the deep love you have for your characters, nor even the attention to providing the reader with an experience they can really make their own and feel connected to. The (potential) LIs quickly feel precious to us, and there are not many MC's that feel as attractive to embody as the Dragon Commander, who you've given so much roleplayability, while never sacrificing the character's soul. That takes some skill, and is worth recognizing. I know you're already getting a lot of love for your good work, but hey, you deserve it, so have some more anyway. Never have enough love~ :D// <3<3