I'm declaring 2021 as Sachiko's 15th OCversary!* And just like Miko, she's got this little piece where previous Sachikos interact with the finalized, official version, though the selection is much simpler - We got the original kid design Leigh (my wife, who was just a friend at the time, btw) came up with, my infamously "wrong colored" Sachiko, and then, of course, Adult!Sachiko with Allié from Raison!

Technically, there would be at least one more Sachiko (the one from the cancelled, original webcomic "Reminiscence & Reflections") but, besides being a lot more rude and snarky, that Sachiko is very similar to the current one (compared to how drastically different R&R!Miko is to Raison!Miko)

*Unlike Miko, though, Sachiko's birthday (December 15) isn't the day she was created. Leigh doesn't remember when, exactly, she created her, but it was definitely before Miko, as an "NPC" like character for a forum-based RP she was part of. Sachiko wouldn't become Miko's best friend until Leigh drew the first art with them in 2007, hence why it gets tricky as to when to consider her creation year...As her current mostly-owner, I say 2006 so she and Miko can just share OCversary years!