>>103608441
Myth and Promise were just designed to get the best they could for certain traits to fill the numbers. Myth especially was a testing ground, basically taking 5 complete individuals and going "Okay, let's see what English fans are looking for" Irys was a test if EN wanted a purely singing idol, but Cover realized "Oh we don't have an English writer for music and they don't really want Japanese songs", Promise was another gen of "Okay, we think we know what the English fans like, so let's test it again. We're still not sure if we're going to commit 100% though."

Advent and Justice were both groups designed to be groups from the start and designed around that professionalism. They went into it knowing "This is a job, and these are the expectations from you. You are expected to be a unit, so can you be team players?" and they were all on board with that from the start. The company also backed them, as units, a lot more heavily than they did with Myth.

As it stands right now, it seems like they're trying to do that with Myth and Promise, but frankly, they're too established as individuals as well as not really enough people for a unit anymore. They could TRY and merge them into one unit, Pro-Myth, but I don't know if they or the fans really want that. For Promise, it would be their third merger, from Council, to Promise, to a new unit all because they've just bled talent.