Numbers

For reference, Kitenshi Kocha's Shirogane numbering system:

Shirogane-senpai: Shirogane Ryou (later amended to Shiromiya-senpai, although she still slips up now and then)
Shirogane-sensei: Shirogane Ryou (KD)
Shirogane-san number mean one: Dahlila Beaumont (later amended to Not-Shirogane-san number mean one after Dahlila objected to being associated with Shou's family name)
Not-Shirogane-san number nice one: Tsumara Fuyuki (later amended to Not-Shirogane-san number doesn't like Shirogane-senpai even though he's the best person in the whole world and I dunno why he doesn't like Shirogane-senpai but he should)