>>42072397Based on the available info I could find by looking at all of the day 2 girl's Twitters, it was very likely Marine, and a very low but possible chance of being Towa. Some of them could've also not tweeted about recordings, maybe they talked about it in a stream, or, they're could've been day 1 girls around too.
I'm locking in my bet right now, Gura's either gonna do a duet with Marine at 4th Fes, or they're working on something else.