I believe Tachibana is loosly based on the real life Samurai Sasaki Kojiro. A young, confident samurai who had developed the Tsubame-Gaeshi technique, or "Swallow Counter" (note Ukyo's Tsubame Gaeshi or "Swallow Swoop" slice). Mushashi and Kojiro dueled on the island of Ganryu in 1612, Kojiro was easily disposed of. Notice the rivalry between Haohmaru and Ukyo in Shodown one and their common stage, Ganryu Isle.
Several other characters, such as Wan-Fu and Kyoshiro Senryo, also have historical references.
That, my friends, is why Samurai Shodown is the greatest video game series ever made.
By the way, many developers that worked on Samurai Shodown also had a hand in creating Ninja Scroll, hence the similarities.