[Epic seven] Nature's Decline and Decay Hell Auto (Earth Advent mode)
Some suggestion just below:
Team 1:
Instead of Zahhak you can use Senya (Just be sure have more atk then Celine)
3 member, instead Leah (i put her lv 5 without equip just for let you understand can be done in duo), you can use: Milias - Violet - Cid - Mort - Pavel - Ervalen etc.
Is quite easy and you can use almost everyone if you have Celine.
Team 2:
BBK
Straze
Mercedes.
Instead BBK you can use A.vildred - Vildred.
Instead Straze you can use Lellona - Lilias red - MLken (full crit) - Charlotte - Landy (destruction set) - wu kong ( maybe ? just s1) - Vivian - C.zerato
Team 3:
Cermia is mandatory then
Baal&Sezan - Eligos - Red tenebria - Veronica - ras (but you need to be sure to kill the boss with the dual) - Jack -o / Shalltear ( as 2nd dps but low spd atk%boots) - Zealot Carmainerose
Note: if you use haste put an artifact that give more chance to inflict more debuff, such as: Torn Sleeve or Alabastron. Same stuff with other characters (like Song of stars - sphere of Inferno or any other usefull)
I put a random one since Cermia one shot anyway the boss.
If you use Ervalen as main dps
you can use
Def down enabler: Iseria (with song of stars) - Bellona - Albedo - kluri
2nd dps Cid - Ram
If you need any help, feel free to ask in the comment...I'll try to help you!