Thinking a bit more about the Dragon Arc -
The bulk of the characterization in this arc goes to Larc and Sierra, and the actual dragons themselves can come across as one-note appearances, especially as Akravator and Jajara are slain in their own quests.
But it's not too bad either, I think of the four dragons as being a representative of the roles dragons usually play in a story:
First off, we have Akravator - I think as a fandom we generally kinda sleep on this guy, what with the unfortunate role as a starter boss, and what with Jajara and Vadise having more unusual and memorable designs.
Akravator serves as the Classic of the group - his name and appearance is what you'd expect from a JRPG dragon. His attributes like being associated with an element (wind in this case) and living on a mountain is also in line with the usual dragon.
Akravator does have a unique aspect to him in that he has several dragoons serving under him when all the other dragons have one. I'm not sure if all Windcallers are considered his dragoons but at least three must be important and powerful enough, serving as barriers in the way.
In that sense, I think we can infer Akravator is also sort a mentor character, a wise dragon in his own way. By the way, if you go out of your way to return to where he is after the Dragon Arc, you can actually re-challenge Akravator to a fight! So it seems he doesn't hold a grudge after everything and is even willing to test your strength under fairer circumstances.
Jajara is what I'd consider the dragon who embodies Mystery - the dragon as a creature one cannot fully comprehend.
Because, really, we don't know much about Jajara as an actual character. Him guarding a Mana Stone seems to be role for the force of good, but the fact that his chosen dragoon is Deathbringer gives ambiguity to Jajara. Deathbringer canonically warred with the Jumi and is implied to be after their cores, is known to brainwash his soldiers, and was looking for "the ultimate firearm" which are all...not very good acts, isn't it? But it's hard to tell whether Jajara approves of Deatbringer's actions, doesn't know, or doesn't care, their relationship isn't really given importance.
Adding to the mystery factor is Jajara's form as a dragon composed of bones. It's definitely a sick character design, ahaha, but he's so different from the other dragons in this sense. Is he undead? The fact that he has a 2nd phase to his boss fight where he rearranges his body also adds to the oddness of it.
We just don't know enough about this guy, and dragons can be representations of that - something powerful, but unknowable and foreign to us.
Vadise's role is obvious enough - she's the Good dragon, benevolent, peaceful and wise.
Vadise's appearance is pretty nonstandard for a dragon, you could even argue she doesn't really look like one, lacking wings and covered with fur rather than the usual reptilian look. Jajara looks odd, but you can still identify him as a dragon, which isn't the case for Vadise. Though, I think Vadise being a fluffy and cute dragon might be a callback to the Mana series's Flammie (and fun fact, Flammie is based off Falkor from The Nevereding Story, as revealed in the art book). The History tome in LOM does state a connection between the Flammie and Dragons, but that's for another post.
Vadise is also different from her fellow dragons in that she lives in the White Forest, a place lush and teeming with life. Akravator does live with multiple dragoons, but Norn Peaks is still a remote location, and while a village exists near Jajara's Bone Fortress, the actual fortress itself is only populated by the undead soldiers. This trait reinforces Vadise's role as one for good, being associated with life.
And of course, Vadise obviously cares for her dragoon, Sierra. She shows concern and affection, but also rebukes Sierra when she's about to do something hasty, and their overall relationship is very close and healthy, which...definitely can't be said for the others lol.
And of course, where there's the obvious Good there is the obvious Villain, and that's where our ol' pal Drakonis comes in. Dragons are many things in different cultures, and one those things is being a symbol of evil, especially in Christian iconography, where the devil is symbolized by dragons in addition to snakes.
And Drakonis does all the evil things - lives in a pulpit of eternal flame, lies for his own benefit, breaks promises, turns people into centaurs, etc.
Appearance-wise, Drakonis is as typical as you can be, being a red dragon and even being associated with fire, the most common dragon-y element. His wings looking more like clawed hands is a bit unusual, but otherwise he looks like what you think a dragon would. It reminds me of the design choice for Fatalis in Monster Hunter, you know, everyone else having more specialized designs, so Fatalis having a classic dragon look makes him stand out.
I'm not sure if this was the intention in writing and designing the dragons, as the art book actually doesn't discuss their creation, despite the Dragon Arc being one of the main three arcs. I'm not sure if it's because those development materials have been lost, or possibly neither Shinichi Kameoka or Nao Ikeda designed them, so they can't provide the concepts. There is concept art for Sierra, the Windcallers, and a cut dragoon character, as they were made by Nao Ikeda, but otherwise the Dragon arc's characters doesn't appear in the art book, sadly.
Another thought finishing this post, generally in fandoms we like the developed or complex characters, so characters that follow tropes, and those with limited appearances at that, don't usually get much appreciation. But typical doesn't mean bad, and there is also charm to be found in making a character whose traits are widely used! So all in all I think the dragon characters are very successful at what they do and I am pretty fond of them all the same.
Vadise is my favorite, but I hope to see more appreciation for Akravator and Jajara as well.
