Kogayane Yumiko is an NPC CO for the UCS Vanguard played by Toshiro, when Kage Yaichiro and the YSS Asuka departed the United Outer Colonies.

Yumiko holds the UOCPF rank of Commodore, and is a Yamataian with jet black hair and deep blue eyes. About six foot three and with D-cups, she is an attractive woman who is aggressive in the waves of love as well as command. She is known for speaking her mind, and extremely loyal to those she deems worthy, regardless of rank.

She is known to have strong feelings for Kotonoha Miyako, who saved her life after the Battle Of Jiyuu]] in early YE 30. She was previously a Taisa, and CO of the NG-X5-18, an Irim-class Heavy Gunship.