If I remember correctly, Adventure would have been an action oriented game, and Legend would have been a turn based game, similar to regular Final Fantasy whose lineage lead to the SaGa series, while Adventure lead to the Mana series. But I didn't play either of them, so I'm being very presumptuous, since they were the first game in either's respective series, vast changes could have been made before they became well known

This intrigues me though. I enjoyed Secret of Mana a bit, it's sadly a little too dated for me these days. Even with the text enhancement mod, the writing is just matter-of-fact, without much character or subtlety for me to really get into. There was one on the GBA that I quite enjoyed. And Legend of Mana was super disappointing. So I'd like to see them extend the series and hopefully it's something I can enjoy. Or at least something the fans can get excited about