The last character to be introduced (I mean main characters) was Jasmine, way way back in update 11 or something. Yes there have been some after, but they are either once-and-done or just-for-flavor and are meaningless. I wouldn't call them "cast", some don't even have a name ( the Spanish maid, the French Cop, the Elevator bride), others that do (Brandy) aren't part of anything.
It is a large group of girls, but they aren't all main characters, and even those have 3 tiers of relevance. MoonBox, has some kind of "schedule" for them to show up (LOL at least I hope he does) and even if the Red Brigade has been very much absent in this Part 2, that by the way is already 11 updates long (wow), I'm sure we'll see them soon. Maybe not before Anne is born. If you have no clue who Anne is, don't worry about it
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So, those that complain of how BIG the cast is, are either very greedy, very focused on a set of girls, or, just want to create a bit of drama because the game doesn't have any...
For a small sect of very patient players (and very suspicious too) there's only ONE new MAIN girl to introduce and add to the main Harem. If you know, you know, if you don't... well... you are very distracted aren't you?
Peace