I've completed the entire game... How sad that all good things come to an end sooner or later. It was interesting to read the impressions of those who played, as well as how they see the plot in both parts.
I'll also allow myself to assume what I saw in these games.
I think that the second part is a continuation of the first part.
After the events of SiNiSistar 1, it feels like a long time has passed. The main character is, judging by the class, a combat mage. A more versatile unit than the warrior Rabiyan.
She knows how to fight, what spells are required, and is more prepared for battles. Perhaps thanks to the heroine's report from the first part.
The events that take place in the game hint that something similar has already happened some time ago. The nuns understood how to fight those who cannot be seen and created a miracle powder, so they could defeat the creatures of the afterlife.
I also assume that the DLC, which will certainly be released, will connect the stories of both parts. The evidence is weak, but...
There are many unrealized ideas that remain in the art or are unfinished, for example - a sword; a white suit, like in the first part (which became available after completing the main game); in the game files themselves there is an unused location.
And this means we have to wait.
And also - to thank the developers financially.
P.s. Thanks for the info about OVA. Didn't know it existed. You guys are awesome!!!
And sorry for my English.