Ryuuguuden is a veryyyyyy weird read, satisfyingly so.
The weirdness of Ryuuguuden, otherwise known as Castle of the Dragon, comes from it's trippy, hallucinogenic, bizarre, scary, and fascinating premise. So it's about these two boys who follow a girl onto a penis shaped train which dives into the ocean and arrives at a sea brothel. Yeah, it's something else. With all this said, you shouldn't let this premise fool into thinking it's going to be trash, the story is surprisingly great.
The direction the story goes at multiple times is often highly creative and interesting, such that you'll often be left greatly surprised at certain
conclusions. The changes in tone throughout the series are also quite unique and offers a refreshing blend that keeps things from being stale. Now, at times I was somewhat ready to drop the series because I didn't like the way certain plot events were going, but I came to appreciate it at the end, all that's to say, give the story a chance to reach its stride.
Often cartoonish, yet at times gritty and somewhat realistic, the art in Ryuuguuden is very impressive, especially given that the author of this series has only worked on a few other one-shots previously. It's unique and has a lot of personality to it, similar to other well-known artists that have their own style.
So there are two main protagonists in the series, Anni and Bo. Now, theses characters are why I didn't rate the series higher than I did. It's not that they're the worst protagonists out there, far from it, but they're admittedly bland and rather cliche most of the time. Bo is the younger brother, mostly naive and easily romanticized by things around him, that's pretty much, and that's the problem. Unfortunately, Bo isn't given much development and remains rather bland. Given that the focus on the series lied on it's crazy plot and is rather short, that's kind of to be expected but still a let down. Anni is a little better, he has moments of moral ambiguity and shows a bit of personality throughout the series, but there isn't nearly enough time for this to shine.
I will say though, the antagonist Hiroshi was quite interesting, I just wish it focused on him and his crazy personality a little more.
This is an interesting read, if you're in to more obscure series do check it out, you're in for one heck of a ride.