I wasn't expecting much when I started reading this, at first the plot seemed interesting, as I don't really see much isekai yaoi often. I don't mind simplistic plots such as this one, because one way or another, it compensates with the characters being 3 dimensional and well-written. I wish I could say the same for The Titan's Bride.
To me, none of the characters seemed likeable at all. The supporting members that show up throughout the manga have 0 purpose and the plot is next to nonexistent. I get that it's a yaoi but with every chapter it's just Caius and Kouichi having sex and nothing more, even at times which feel inappropriate due to whatever internal struggles that Kouichi is facing, granted that he has been suddenly transported into a whole new world with no ability to contact his friends and family and essentially being forced to be some random rich man's bride.
The power dynamics between their relationship is what made me feel uncomfortable throughout, and it gets even weirder when you realize that Kouichi is (implied to be) a high school student is having sex with a full grown man, part of me even wondered if Kouichi was experiencing some sort of Stockholm Syndrome. Furthermore, their relationship has practically 0 chemistry and all the sex scenes are very forced. You could strip away the very little plot that this manga has and keep all the sex scenes and nothing would have changed. There is no substance and I found myself getting bored even 5 chapters in.
Really, the only good thing I liked about this manga was the art style, as it's what got me interested in the first place. At the time of writing this there are 70 chapters, so unless you like 70 scenes of size difference hentai I don't recommend this manga.