Your actual team has no defense at all. Rearguard Sergeant, with decrease attack and ally protection, is a great champ for CB.

I would probably remove Rotos from the team, for several reasons, even if he is your best damage dealer right now in the screenshot. The decrease def debuff from his A1 would be redundant, as the Sergeant does the same, and his extra turns would make the ally protection expire early on. If he is not in your CB team anymore, you can concentrate on what he does best, fighting in arena.

Another way to get more damage is visiting the Minotaur and get Warmaster (Giantslayer for Ronda) as tier 6 mastery for all your champs. Even supporters like Doompriest will do a million damage with that mastery over the whole fight. Every champ in your CB team should be lvl 60 and have Warmaster/Giantslayer.

OK thanks, do you think I should include morag?