This is the dinner party scene at the Scarlet Devil Mansion from Silent Sinner in Blue chapter 9. Translation by Solamarle. I added all the notes and tags today. Some people say that the character at the upper left between Minoriko and Kaguya is Keine, but I think she looks more like Tenshi.
Tenshi first appear in 10.5 after SSiB chapter 11. So, she can't appear in this picture. That girl is Flandre bcoz we can see her unique crystel wings.
I changed the translation note, but I kept the question mark because Flandre wears a necktie, not a ribbon like that (OTOH, Remilia is already wearing a special costume for this occasion.) Also, in Inaba of the Moon and Inaba of the Earth, Reisen and Tewi left the party and ran into Flandre in the basement.
Sabre said: Tenshi first appear in 10.5 after SSiB chapter 11. So, she can't appear in this picture. That girl is Flandre bcoz we can see her unique crystel wings.
I doubt that girl is Flandre. There is a chapter in Inaba of the Moon and Inaba of the Earth that takes place concurrently with SSiB, and in that chapter, Tewi and Reisen wander into the basement and encounter Flandre (to be precise, only her shadow), thus proving that she is in the basement at that time. However, it is possible that she went into the basement after they went in there, so you may be right as well.
It's strange to see Lily White there... In the three fairy's manga (can't remember wich one) Remilia wanted to capture Lily White and it was showed like an almost impossible task. Lily just passes and inmediately goes away because (aparently) it always becomes spring in any place she stays...
I would still say that the mystery character is Tenshi. What we can see of her matches her design too well in my opinion. This could be a sneak peek of Tenshi, or her character design, before SWR's release.
This makes me think how would the lunar invasion would be like, but instead of some girls (reimu, marisa, yuyuko, youmu, remilia, sakuya(?) and yukari), they would bring some of other gensokyans (except kosuzu, cause i don't think she's that good in combat, and hieda, due for someone has to keep writting the chronicles) peoples on it? (as well how much rockets are they gonna need exactly?)
EDIT. Speaking of said question... when in the timeline of the games was SSiB releas exactly? (after MoF and before SA?)
...So,I just can't get used to standing around and drinking.Maybe I should have brought a cushion.RumiaWriggle NightbugBlaBlaBlaSunny MilkLuna ChildStar SapphireCirnoKirisame MarisaSaigyouji YuyukoHakurei ReimuKonpaku YoumuMoriya SuwakoKazami YuukaAki ShizuhaMystia LoreleiLily BlackHouraisan KaguyaLetty WhiterockYakumo RanChenHouraiYasaka KanakoKawashiro NitoriInaba TewiFujiwara no MokouPatchouli KnowledgeRemilia ScarletShameimaru AyaOnozuka KomachiAlice MargatroidIbuki SuikaYagokoro EirinIzayoi SakuyaFlandre Scarlet (?)Shiki Eiki, YamaxanaduIt'd be weird for you to sit on a cushion like that here.Kochiya SanaeAki MinorikoNameless maidWith this rocket, we'll be able to sneak into the Moon!Lily WhiteReisen Udongein InabaMedicine MelancholySu-sanLunasa PrismriverMerlin PrismriverLyrica PrismriverKagiyama HinaHieda no Akyuu