Taizo Tachibana is a Captain in the JSDF Navy. He commands the Wet Navy's Riganryū, a heavy destroyer in command of a small detachment. He takes commands from Admiral Watanabe Iwao.
He was present on Nippon during Exon and UNSC's invasion. Since he was part of the Wet Navy, there wasn't much his group could do, since all of the ships which could engage at a safe distance were large battleships or carriers, vessels which were effective at long range and non-naval targets. As a result, he was forced to watch the destruction happening on the ground, and was more than relieved when the invasion forces finally pulled out.
After the invasion, he wasn't immediately told about the status of his family, which mostly consisted of his daughter and siblings, since much of his family had passed away earlier in his life. It took a great deal of time before they revealed the information, and focused more on transferring him, and much of the Wet Navy, into an "amphibious" space Navy which could operate both in space and on water, as part of a new war method. As keeping with his rank and original position, he was put in charge of the now amphibious destroyer Riganryū in command of the same group, under the same Admiral Watanabe Iwao. A new Ensign was granted to him, Yuki Nagato.