I don't remember what the maid's name is...

...Well huh, happened to find it on another post: Suzuno Ayumu.

Tagged as translated since the only missing text is too small to be readable.

To be honest, I'm surprised that people in the anime didn't consider Ayumu to be the fifth player. Since she did arrive with the others, that could be a reasonable misconception, no?

Well she wasn't in the school uniform, and it's probably not all that uncommon for Touka to be seen with a maid.