Uh, no?

The definition of arrogant is "Overly convinced of one's own superiority and importance" (thesaurus). There are other definitions but all to the same effect. The fact that it includes the word "overly" means that it is not justified, unless of course you are trying to say that justifying is simply making an excuse for acting like an ass like most people do.

In Kei's case, he is practically perfect in everything he does, and is the best in all fields. Its not arrogant to state that fact, and he never goes around and offends other people flaunting it.