Help beat Astranyx!! | Raid Forum (plarium.com) 

Cookie-cutter strategy is a TM booster first to assure your team goes first, followed by a debuffer (if needed), followed by a nuker, followed by as much enemy TM control that you can get.

The key is that you want to wipe all the clones with your nuker in the first turn, and then focus the boss down. Keeping her from taking turns helps greatly, so any TM reduction and/or speed debuffs you got is important if you have it. Otherwise you'll just have to pump out as much damage as you can and hope you can kill her quickly. Don't use a team that is too tanky, or it'll prevent you from killing them. The better TM control you have on the boss, the more glass cannon-y can you make your own team. If you can't prevent her from taking turns, you'll probably need to make them a bit tankier or include some sort of heal mechanism (e.g. a healer, leech or regeneration/immortal gear) so they survive her hits.

Another option would be to have a CC champ go first. Remember that since they're a copy of your team, you'll always go before they will. With the champs you listed - Ragash has AOE CC, so if he's your fastest champ, you'll stun their team before they can act, and then you can take your time finishing them off.

Yakarl, Kimi, Deacon, Allure, Arbiter (careful with this one cuz if u dont kill her in 1 turn she will revive everyone), etc. All those champs have either cc, tm boost, tm reduction or both. You should avoid tanky champs. Champs with passives that heal or give unkillable *leorius, irongut, vogoth, skullcrown*, ress champs (if you dont have anything better than arbiter, ignore this) and ideally have one champ that is very paper but with a lot of dmg so it gets copied individually and killed quickly. In case u cant avoid Fae taking a turn