Talk:Events/@comment-1465604-20160121174021/@comment-25298888-20160123133029

Actually, Riverta isn't the same as Rememo or the others, as she's not part of the 5* quest. To get her in Japan, you had to clear all of the sub-quests for the event in order to get access to a hidden quest, where she is the 1st clear reward. Quest has three rounds of fodder and the boss round is Riverta with two flankers. It looks like she doesn't drop either, so no farming.

Not sure if they would give us the hidden quest, so using her as a 20th clear spirit is a possibility.