Another Tuesday, and another Tsundere. With this week's addition we have what I like to think is a pioneer in the Tsundere frontier, as she is one of the most purest and easily defined versions of the term. While the tsundere type of character has been around for nearly as long as anime itself (or I supose any work of fiction, Japanese or not), the term was given birth on the Internet due to the overabundance of these type of character in anime/games/books/manga, and Akiha was on the cusp of the birthing of the term.
Akiha is one of the female protagonists in the Visual Novel Tsukihime. Tsukihime also spans an anime series (which is horrible) and a video game series, Melty Blood (which is excellent), and Akiha is present in all those incarnations as well.
As stated before Akiha is the purest form of Tsundere, as she is cold and calculated towards the main protagonist, but once he spends times with her she is more then willing to let her guard down and show her softer side (if you catch my drift). She also has an almost uber-Tsundere super power, in her ability to steal energy from other people (usually blood), which turns her hair red and makes her a lot grumpier then normal.
However, poor Akiha is swarmed in tragedy. In the original Tsukihime Visual Novel she is the only female protagonist who doesn't have any kind of a happy ending. This is rectified in the sequel, Kagetsu Tohya, probably from some fan outrage.
Perhaps one of Akiha's greatest accomplishments was paving the way for her successor in the Tsukihime follow up, Fate/Stay Night. There is a lot of Akiha in Tohsaka Rin. Tohsaka is a lot friendlier, but to say these two don't share more then a few traits (and mannerisms) would be naive.
Regardless she is her own beautiful fiery tempered character, and deserves to be celebrated this day.