Before he could begin to comprehend what on earth was going on, the beautiful Goddess Belldandy warped into Keiichi's dorm to grant him a wish.

At his supposed graduating from college (ch 78, he was one class shy), he started working at the repair shop Whirlwind owned by the founder of the NIT Motor Club: Chihiro Fujimi.

23 of the manga, he and his family are originally from the Kushiro subprefecture in northeastern Hokkaidō (the northern island of Japan).

He is also rather intelligent; for example, once he answered a test full of complex chemical and mechanical questions in two minutes flat while the other students were struggling with more conventional problems.

Finally, he also seems to exhibit unadulterated purity in his actions; he helps out others in need, he rarely complains about setbacks, and always attempts to be truthful about any situation.

Faced with a situation where a goddess was now bound to a mortal, heaven placed this seal in order to maintain the 'separation' between gods and men.

He relishes creating unusual motor vehicles when presented with a challenge, usually by one of his seniors – Tamiya, Otaki or Chihiro – and laughs like crazy during a heated motorbike race against his father.

In the manga, he can play acoustic guitar, and is a fan of singer Matthew Sweet, possibly due to his quirky upbringing (in the original Japanese, it's The Carpenters).

This is shown in the Traveler arc in 18, when he befriends a Schrödinger's Whale (a being that lives in a 5-dimensional quantum state) that is attracted to a storage room artificially expanded by Skuld to infinite capacity; he teaches the friendly whale some of his songs when he (for Belldandy notes it is male) shows curiosity in CD he's playing.

In the manga, Keiichi's personality was illustrated when he was able to summon one of the Valkyrie Lind's own Angels, Cool Mint.