I feel like Anskks mass sleep is a bit too overpowered considering that unless I miss something there is no way to grant your party any kind of status resistance or immunity. I only manged to beat her after multiple tries by getting lucky with silencing her despite her resistance as otherwise she could wipe my party instantly just by using mass sleep twice and putting the entire party to sleep. After that point there was nothing left that I could do as she would just spam poison and sleep so that none of my characters could ever wake up