Evolution
Considering that Kosuke Fujishima has been drawing the Oh My Goddess! manga for over fifteen years now, it's inevitable that the style of his artwork has changed over time - often for the better. The Belldandy who first appeared in Keiichi's dorm room bears very little resemblance to the Belldandy that we see today, and the same is true for most of the other major characters as well. Mara is no exception. Thus, this page is an attempt to analyze how Mara's appearance has changed as Fujishima's artwork has improved.
I divided this page up into three sections that correspond to the three different sections in the scans gallery. You will notice that on this page, I often link to images from the gallery in the body of the text, in order to provide examples of what I'm talking about. You can read this page as a sort of running commentary on the gallery, if you'd like, since quite a few of the best images in the gallery are linked here, anyway.
-----> Early Mara
When she first appears in the manga, Mara is drawn with poofy hair, baggy clothes, a rounded face, and wide, large eyes. Notice her flat chest and almost sexless body in the image to the left. It's no wonder that Keiichi initially mistakes Mara for a man.
The outfit to the left is the only outfit that Mara wears for most of the early part of the manga. She only ever changes her outfit once, in the Lord of Terror story arc. Her second outfit, however, shares a lot in common with the first - namely, the baggy dark clothes paired with a cape. Mara's fangs first appear in the Lord of Terror story arc, too.
Mara has the red triangles on her cheeks from the beginning, but the markings on her forehead are not shaded in, and appear to be almost the same shape and color as her blonde eyebrows. This version of Mara does, however, establish a few of her distinguishing traits that will remain throughout the series, such as her excessive wrist and neck jewelry, her gloves (she is always wearing gloves with the fingers cut out), and the way that her hair is much longer in the back than it appears in the front (sort of like a long, curly mullet).
That, and her hair is often drawn in a style reminiscent of snakes. There are many panels in the manga where Mara's wild, unruly hair makes her look like some sort of Medusa. Fortunately, her hair starts to calm down a little bit toward the end, although not by much.
Finally, in chapter 29, after it is decisively revealed that Mara is a woman, she starts to be drawn with a little bit of a chest. But really, just a little bit. Were it not for the two curved shadows peeking out from underneath her baggy shirt, you wouldn't be able to tell that there was anything there at all.
-----> Middle Mara
From sexless to sexbomb! Mara returns from a long absence after the Lord of Terror arc sporting a scandalous new outfit, tightly curled blonde hair, pronounced fangs, and most noticeable of all, a gigantic chest. In her mini form, it looks as though Mara's boobs are going to pop right off her. Mara still loves her capes, but her next set of outfits are tight, revealing, and leave little to the imagination. She also seems to favor a bondage theme, wearing lots of leather and metal and strappy things. And yes, each and every one of her outfits still includes gloves with the fingers cut out. Her outfits themselves, however, are starting to look increasingly, um, uncomfortable. Like I said, it's that bondage theme she's got going.
It is worth noting, however, that during the Devil Urd story arc (Mara's last appearance in this stage of her evolution), Mara does make an effort to dress a little bit more like a normal person. Well, a normal person wearing skull-and-bone jewelry and a very tight, very short pair of denim shorts, that is. This is most definitely Mara's sexiest phase of evolution.
In addition, Mara's face and hair are drawn with increasing detail. Her hair in particular improves drastically. Unlike the poofy, ropy, snake-like mess she had on her head before, Mara's hair in this stage is tightly curled, almost kinky, although still somewhat wild. Her hair is still much longer in the back (nearly down to her hips) than it appears in the front, although a few longer strands are starting to find their way in front of Mara's shoulders. As for her face, its overall shape becomes more refined, with noticeable cheekbones and chin. Her eyes are no longer rounded, but drawn with sharp, angular shapes and pronounced eyelashes. From chapter 60 onward, the markings on Mara's forehead are shaded in to match the markings on her cheeks, and her fangs become a permanent part of her appearance, even when her mouth is closed.
-----> Later Mara
Mara's hair evolves from tight, kinky curls to a more flowing, wavy style, although it could still definitely be described as "curly." The shape and style of her hair is more defined, too, especially in the way that it frames her face. Mara's hair goes through an intermediate phase in the Queen Sayoko arc, and then takes its final form in the Hild arc (volume 22), much later.
Like the rest of the cast, Mara's face is drawn increasingly rounded, while the overall shape of her body gets thicker and shorter, reflecting a more realistic figure. Her chest becomes smaller too, and in the Rind arc it seems to almost disappear completely. More noticeably, however, the way that Mara dresses herself changes. Yes, she still has her leather getups and her sexy chains, but she also begins to show some less revealing outfits as well. Mara's later outfits in the Queen Sayoko and the Rind arcs tend to be much, much more conservative than before (i.e., see her outfit to the left). Also, Mara breaks her tradition of open-fingered gloves, first by wearing whole gloves a couple of times, and then finally by wearing no gloves at all. If I'm right, I think that the Rind story arc is the first time that Mara has ever not worn gloves in the manga. (Not counting the few times we see her nude, or lounging around an onsen in a bath robe. I mean really not wearing gloves with one of her outfits.)
This final stage of Mara's evolution (so far) has transformed her into a subtle, stylized beauty, which is a far cry from the bombastic voluptuousness of her middle stage, or the unattractively drawn androgyny of her debut chapters. If the Oh My Goddess! manga keeps going, we may see yet another change in the style and form of Fujishima's artwork, and perhaps Mara will get another makeover again. Who knows? Only time will tell.