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.
Actually, it's pointless if you don't stand out.Ryuumonbuchi ToukaAnd also!Wh- What's with the maid...Ryuumonbuchi has arrived!The champions of last year's preliminaries! Kunihiro HajimeInoue JunSawamura TomokiThere was no one like that last year...You're standing out, you're standing out!You're standing out in the wrong way.Could it be that she's entering this year?Ryuumonbuchi