Complex sentence: The game takes place 19 years before "Seiken Densetsu 3", and features an all new cast of characters, as well as a few returning heroes from Seiken Densetsu 3.
Split into simpler sentences: The game takes place 19 years before "Seiken Densetsu 3". It features an all new cast of characters, as well as a few returning heroes from Seiken Densetsu 3.