BrownDust-ism.

Addicted To Gacha

Co-op Raid Dolan

☆☆☆ Hard Fastest (2020-05-25) ☆☆☆
This takes 13 turns. Info is from しろくろ's Twitter.
  1. ★6 Freesia+15 (Wave 2: Kill 9, 10, 4, 7, 2)
  2. ★6 Shoman+15 (Wave 2: Kill 1, 5, 8, 3, 6)
  3. ★6 Christina+15 (Wave 1: Kill 8, 10, 3)
  4. ★6 Lian+10 (Wave 1: Kill 11, 6, 9, 5, 8)
  5. ★6 Cecilia+15 (Tanking the boss)
  6. ★6 Jin+10 (Wave 1: Kill 2, 4, 7 by counter)
  7. ★6 Helga+12
  8. To be killed
☆☆☆ Hard Flexible (2020-01-10) ☆☆☆
100%, and you can use this as it is even when somebody starts the fight first or joining someone else's fight. This takes 22 turns. Require Granhildr+15. The front 4 are there to be killed by 2, so that Eindolin will increase her support power. All enemies who attack Granhildr except Dolan should be kill by reflection.
  1. ★6 Refithea+12
  2. ★6 Chalkle+10 (Wave 2: Kill 8, 2, 1)
  3. ★6 Eindolin+10
  4. ★6 Granhildr+15
  5. ★6 Lian+10 (Wave 1: Kill 11, 6, 9, 5, 8)
  6. Others are all to be killed
☆☆☆ Hard (2019-12-08) ☆☆☆
100%, and you can use this as it is even when somebody starts the fight first or joining someone else's fight. This takes 26 turns. Granhildr+10 and Refithea+12 combo can do just about enough reflection to kill mobs.
  1. ★6 Refithea+12
  2. ★6 Mary+10
  3. ★6 Chalkle+10 (Wave 2: Kill 8, 2, 1)
  4. ★6 Helena+10
  5. ★6 Eindolin+10
  6. ★6 Granhildr+14
  7. ★6 Lian+10 (Wave 1: Kill 11, 6, 9, 5, 8)
  8. To be killed
  9. To be killed
☆☆☆ Normal (2018-10-29) ☆☆☆
There is a good possibility to clear all.  Using 3 tanks, but Grosa, and Granhildr are main tanks, and Seir is more like backup.  Garinoth will hit 4 on Wave 1, and he will do good damage.  In result it will get much easier after that.
  1. ★6 Anais+9
  2. ★6 Grosa+9
  3. ★6 Vincent+9
  4. ★5 Garinoth+1
  5. ★6 Seir+8
  6. ★6 Veronia+9
  7. ★6 Viola+9
  8. ★6 Elizabeth+0
  9. ★6 Granhildr+3
☆☆☆ Normal (2018-10-05) ☆☆☆
At this moment, I use this formation.  With this I can go around 85% in normal.
  1. ★5 Eunice+9
  2. ★6 Grosa+9
  3. ★5 Vincent+9
  4. ★6 Rafina+9
  5. ★6 Veronia+9
  6. ★6 Viola+9
  7. ★6 Anais+9
  8. ★6 Astrid+6
  9. ★6 Angelica+3
Tip from YouTuber チャンネルハックン.