In Japan blood typing is a common practice, similar to Astrology in the Western countries. It's also a big superstition that is often taken to extremes. There are many examples of this in Japanese society. For instance, during World War II the Japanese army was divided into groups according to blood type. Some schools even divide their pupils in this manner, and teach them in a way that is said to be successful for their blood type.

On the lighter side, characters in many Japanese stories are given blood types so one can determine their inherent strengths and weaknesses, and even for the purpose of pairing them up properly. (An O/A match is considered ideal.)

Because blood types are classified using a list of specific traits, and because there are only four to choose from, it's easy to ascribe a blood type to characters like Dekar who didn't get one. What follows are descriptions of the four blood types:

Type A ("farmer")	Outwardly calm, inwardly uptight, conservative, introverted, reserved, patient, punctual, perfectionist, obsessive, stubborn, sensitive, sneaky, cautious and careful.
Type B ("hunter")	Creative, passionate, animal-loving, strong personality, optimistic, flexible, easy to get along with, adventurous, forgetful, irresponsible and self-centered.
Type AB ("humanist")	Well aware of his or her surrounding environment, cool, controlled, rational, introverted, critical, indecisive, aloof and unforgiving.
Type O ("warrior")	Strong sense of purpose, ambitious, athletic, robust, self-confident, romantic, proud, loyal, natural leaders, easily influenced, arrogant, insensitive and ruthless.

Though no blood type is a perfect match, the one that suits Dekar best is the O type ("warrior"). Although he never gets the title of party leader, his behavior is typical of such: the scene-stealing, the daring rescues, the solving of party problems. During his travels with Maxim in Estpolis II, it seems like there are two characters leading the party! And in Estpolis Gaiden, while not as exuberant as he was in his youth, Dekar still manages to get things going for Eldin and his friends. During numerous occasions he steps forth with a general command over the situation.

It's easy to see that the A and AB types wouldn't work for him at all. B types are seen as loose cannons; while they appear to be outgoing and leader-like, they are really too fond of freedom to accept the burden of responsibility. In contrast Dekar doesn't seem to be thrown off by responsibilities at all. For instance, while he acknowledged to the King of Bound that chasing after Prince Alex was growing tiresome in Estpolis II, he never neglected to carry out that duty.