Im not sure someone writing guide to speed farm megacryst on this. just want to share my best one.

Map

1. start on Endless Cliff map. collect 2 point then moving on Fading Coast(number 2 on picture). forget the last one unless you want to waste more 2-3 minute in maze for just 1 collection point.

2. You need 1 unit to immune everything include dead to protect all of your team. my team is 3 hayate WoL Ayaka. all equip charm bangle except Ayaka has equip with Safety bit and producer jacket.

that's it. I have pretty decent time so far (4 times). On avg I spent 20 min. best run is 15 min.

megacryste per run is around 55 - 70.

edit : best run so far; 4 hayate 9 charmbangle = 9.24 minute. full clear.