What volume does seiya kou appear in sailor moon?

Seiya Kou, the Sailor Starlights' leader, doesn't appear in the original "Sailor Moon" manga by Naoko Takeuchi. He is introduced in the "Sailor Stars" arc, which is the final arc of the anime series, based on the manga's ending. This arc was not adapted from the manga and is therefore considered an original anime story.

So, while Seiya Kou exists in the anime, he doesn't have a specific volume in the "Sailor Moon" manga.