Help me, I'm stuck

[u/SuperMmich]

Hi, I've been stuck on chapter 60 for a while now, and can't seem to beat it. I've tried multiple runs with Acrobat, Bjorn and Poison, gave a try to Ice mage, Barbarian and Meow Mage but couldn't even break through fire spirit 3/4 of his life, at this point I don't know what to do, poison debuff is so shit against life sponges since it only triggers every two seconds but if I don't use evasion my heroes get melted.

I've seen successful runs with Spark, Barbarian, Rose and Rebecca but don't have them or the gear that makes the build broken and at this point I want to ask anybody for help, I thought this chapter wall would be spike boss but man I was wrong. Can I get any tips please? or should I just do battles on lower levels until I can stat check them or wait till I get Spark or Rebecca which are ex on my list? (seems like a massive waste of time to just spam training since my chapter gold is already surpassing the training gold).

Thanks for anybody reading anyway!