Yoshikage Tachibana is the father of Tomoe Tachibana. He is rather protective of tradition, but his disapproval of Tomoe's choice to pursue a career in endoscopy resulted in Tomoe having a fight with him and leaving the clan for America.
In Tomoe's storyline, he calls her back to Japan. His messengers tell her this is due to an illness, but in actuality Yoshikage is dismissive of the elders' concerns about his health, and upon Tomoe's return he tells her that the real reason he called her back was so that he could arrange a husband for her, enabling her to continue the Tachibana line. He collapses due to pneumothorax. Needles cannot penetrate his skin, so Tomoe does endoscopic surgery on him to seal the ruptured bulla in his lung. While he is recuperating from the successful operation, Tomoe takes a flight back to America, saying she needs to "train" further (continue her surgical practice). He has grown to accept her choice.