Dekar's appearance has evolved throughout the Estpolis series. Here is a closer look at all official artwork of him.

Ryu Kurugami is the character designer for Estpolis Biography II. His manga-style images are full of detail and imaginative flair, and are well-suited to the mostly medieval environment of the game. The characters he created are serious in demeanor, with subtle facial expressions and languid eyes. He created a very grave-looking Dekar, especially in the first image. He is a petulant looking young man, looking off to the side. He is pouting as though he isn't being paid any attention. He stands in full armor, sword and shield at the ready. Unlike fellow swordsmen Maxim and Guy, Dekar wears a full suit of armor, befitting a soldier in a royal army. We can also tell by his features that Dekar was designed to be a handsome character, the "pretty boy" type.

In the second image Dekar is a bit more playful, brandishing two swords crossed before him, his hair flying high. His skin is much darker in this, and his armor has more of a violet tinge.

There is some disagreement among fans regarding the nature of the red streak in Dekar's illustrations. Is it part of his hair, or a feather on his helmet? In the first image, it appears to be more of the latter. In the second image, it seems to be a part of his mane. In Dekar's in-game rendering, there is neither a red streak nor a feather to be seen. Instead, there is a bright purple sheen on his hair when he's facing forward.

Dekar's spiky hair doesn't appear in either of Kurugami's illustrations. It became his trademark hairdo for his in-game rendering.

Estpolis Gaiden saw very few changes to Dekar's original design. The artist's style here is distinctly anime in nature. His armor remains the same, only lighter in color, most likely to fit the palette used for the rest of the cast. On the Japanese box art, Dekar is shown in a shade of blue closer to his original design, with a look of pride on his face that only he could muster, as he stares off into the distance. Of note, this is the only Estpolis game box that Dekar appears on.

In the in-game renderings, Dekar's hair color is lighter to reflect his age. In the portraits inside the text bubbles, we see scars on his face, perhaps a sign of all the battles he has survived. This is also the first time we see Dekar's red cape in any Estpolis game. The makers of Est Gaiden made efforts to stay as true as possible to the first Dekar designs.

Here the world of Estpolis was changed from medieval to steampunk, so an appearance overhaul was needed for the entire cast. Character designer Yusuke Naora redesigned Dekar with quasi-modern attire. His red cape became a flashy long coat. He carries no weapons, but is instead armed with gauntlets — a representation of his ability to use any weapon in combat. Unlike Kurugami, Naora put more expression into the characters. Particularly, in the released full-body illustration, Dekar sports a wide, cocky grin that so accurately represents his over-the-top personality.

In Lands, only Selan has blue hair. The other blue-haired characters (Tia and Artea, in addition to Dekar) endured color changes when redesigned. Concerning Dekar's new hair shade, the game's developers looked to the red streak in his hair in the previous games. While described as an "extraordinary hairstyle" for the previous time periods, Lands' developers were looking for, apparently, an even crazier color. As they recall on the official Japanese website, "At first, there were jokes such as 'How about pink?'" But soon the joke became an idea taken seriously. I personally disagree with this decision — the color fits a female character, perhaps one with a mild personality. Square Enix, save your jokes for the dialogue!

One thing that remained true to Dekar's original design was his pretty boy status. In fact, in Naora's redesign, Dekar's features are even more refined, perfectly blending delicate with masculine.

Among the media released for Estpolis: Lands was some character wallpaper. In the group picture Dekar can be found in the bottom right corner, sporting a more serious expression.

Prior to the release of Estpolis: Lands in Japan, the Estpolis Audio Drama series was released. The logo for this series is an example of the super deformed art style. Dekar can be seen in the center of the logo, facing off with Guy.