I've played 14 10-set DF gacha and got 5 4⭐ (dupe DF Arisa). So my drop rate is about 3.57%.

My strategy to play DF gacha is when my drop rate at one current time above 6%, I'll play no more. And if my current drop rate below 6%, I'll play until it reaches 6%. So, it has not worked this time. I think the more I play, the gacha drop rate will go near around 4% point.

Next time? Hmm, there is no next time Q~Q