Well I used AW Bernice with Keykii strat and got 'lucky' because I accidentally let single goblin mage pass so Main Boss just walk past Bernice. Otherwise I'm sure she'll block him. I realized it when my Bernice taking quite a damage when her skill is active. Luckily I have enough UP to deploy mage and my healers are competent (Alissa Iris AWFedora). And everything went well as Thetis dueling Main Boss with Despara-Sasha-Calioppe supporting her.

Got 5 rogues so far, but with only 1 Ruby drop despite Cuterie on team. Weird.