BrownDust-ism.

Addicted To Gacha

Underground Evil Castle 46 to 50F

Despite the hint in the game suggests to scarify friends in order to lower boss's DEF, in reality it's pretty difficult to do so. I suggest simply use skills that can ignore DEF.

☆☆☆ Underground 46F (With Seto) ☆☆☆
While relay on Benshina's taunt to protect Seto, Seto needs to be sit next to Benshina so that Seto is in boss's AoE.
  1. ★6 Benshina+15
  2. ★6 Seto+13
☆☆☆ Underground 46F (With Levia) ☆☆☆
Deka needs to follow Kaylin, so that Deka will kill mobs that Kaylin attacks. This way she will not be killed by Combat Stigma. If you have Granhildr it will be even easier.
  1. ★6 Levia+12
  2. ★6 Kaylin+7
  3. ★6 Deka+15
☆☆☆ Underground 47F (With Seto) ☆☆☆
  1. ★6 Wiggle+10
  2. ★6 Seto+13
  3. ★6 Benshina+15
  4. ★6 Zakan+10
  5. ★6 Chalkle+10
  6. Meat Shield
☆☆☆ Underground 47F (With Levia) ☆☆☆
  1. ★6 Levia+12
  2. ★6 Kaylin+7
  3. ★6 Deka+15
☆☆☆ Underground 48F (With Seto) ☆☆☆
  1. ★6 Wiggle+10
  2. ★6 Seto+13
  3. ★6 Benshina+15
  4. ★6 Zakan+10
  5. ★6 Chalkle+10
  6. Meat Shield
☆☆☆ Underground 48F (With Levia) ☆☆☆
  1. ★6 Levia+12
  2. ★6 Kaylin+7
  3. ★6 Deka+15
  4. ★6 Scarlet+15
☆☆☆ Underground 49F (With Seto) ☆☆☆
  1. ★6 Benshina+15
  2. ★6 Seto+13
  3. ★6 Wiggle+10
  4. ★6 Chalkle+10
  5. ★6 Zakan+10
  6. Meat Shield
☆☆☆ Underground 49F (With Levia) ☆☆☆
  1. ★6 Levia+12
  2. ★6 Kaylin+7
  3. ★6 Deka+15
☆☆☆ Underground 50F (With Seto) ☆☆☆
  1. ★6 Edin+13 (Assult+Rage runes)
  2. ★6 Dalvi+15
  3. ★6 Seto+13
  4. ★6 Helga+15
  5. ★6 Zakan+10
  6. ★6 Wiggle+10
  7. ★6 Chalkle+10
☆☆☆ Underground 50F (With Levia) ☆☆☆
  1. ★6 Levia+12
  2. ★6 Kaylin+7
  3. ★6 Deka+15
  4. Meat Shield