「CounterSide SEA」Rebuilding the Octaseal Domain - Nanahara Alliance Challenge Mode w/ Auto Play 

Probably the most Easiest Challenge. Hope this will help.
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Here's my Team in order & Gear each challenge :
- Challenge 1-1
1. Lee Yumi (EVA Set)
2. Gaeun (ATK Set w/ Skill Haste Substat)
3. Kyle Wong (CDR Set)
4. Eins & Zwei (HP Set)
5. Nanahara Chinatsu (CDR Set)
6. Nanahara Chifuyu (HP Set)
7. Rita Arsenico (CDR Set)
8. Edel Meitner (ASPD Set)
- Challenge 1-2
1. A.Hilde (HP+DEF Set)
2. Rita Arsenico (CDR Set)
3. Nanahara Chifuyu (HP Set)
4. Xiao Lin (ATK Set w/ Crit Dmg Substat)
5. Evelyn Keller (CDR Set)
6. Eins & Zwei (HP Set)
7. Gaeun (ATK Set w/ Skill Haste Substat)
8 Shin Jia (ASPD Set)
- Challenge 1-3
1. A.Hilde (HP+DEF Set)
2. A.Seo Yoon (ASPD Set)
3. Evelyn Keller (CDR Set)
4. Gaeun (ATK Set w/ Skill Haste Substat)
5. Nanahara Chifuyu (HP Set)
6. Eins & Zwei (HP Set)
7. Rita Arsenico (CDR Set)
8. Edel Meitner (ASPD Set)
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BGM : Annabel - Re-Vanishment