Bell

Bell's Active 1 targets the main attacker, so it's tough to go head-to-head with Cordi in quests with high firepower settings. Strategies include: ① Defeating Bell in one hit before it deploys infinite shields ② Bringing characters like Yur who can nullify buffs ③ Preventing Bell's Active skill from activating with characters like Luna As for progression, I don't think it will end, but once Cordi's magic gear is complete, you should strengthen your sub-attacker similarly to Cordi.

④ Infuse Mimi with Resonance to damage the target resonating with Bell, indirectly defeating Bell. ⑤ Use Merlin's Active 2 to shatter Bell's shield. ⑥ Use Nina to steal Bell's shield. …Are these options viable too? Since the poster seems to be focusing on Cordy, ⑤ might be difficult…(´-ω-`) Refer to ④ and ⑥. ( ´∀｀)