Someone named Sato (咲斗) was a former member of this band.

I think that Sato (咲斗) is a name used by bassist Kikyou (桔梗) after ￠ar†varia disbanded for the first time, as a later version of Kikyou's official website had “咲斗” in the title. That being said, Sato's homepage has “yue” in the address, so it's also possible that Sato is vocalist Yue (憂絵).

Whoever Sato (咲斗) is, he's hard to track, as he seems to have used a different name in each band.