When it comes to Mouch, I mainly play her with Caro units, but Clementine does want to play the first command card each turn to give more strength. The few times I've played Mouch Ultra, I just annihilate the ultra zone for that +1 arith and +1 card from the insight. At the end of the day, Mouch gameplay tends to be scaling/gathering resources while depleting the first hp bar, then burst in one go for the second.
Faint is really good because her exalt gives really good amounts of death res, we are talking +150% DR at exalt lvl 6. Weakness for 2 turns on devour is also pretty good. It's extra survivability and, for Mouch, it's also +100% Crit DMG per DR triggered (check her e1). Give her two DR wheels, survive 2-3 DR triggers and watch her maul the boss. I also like to save her rouse for when I'm ready to burst all the way, since the Mortal Blast copy you get from it is fleeting. I guess it depends on the situation.
For Caro, do the following: if boss has +1 hp bar, chip at it with saya's 0 cost + strikes (use the posse to draw after discarding your hand, you can destroy other awakeners strikes if you really need to) while surviving and building exalt, until you have Thais/Helot/Mouch exalts ready. Once you are ready to obliterate the boss, 0 cost Saya, then rouse Mouch, then exalt Thais to copy the created Mortal Blast, then Helot and Mouch's exalt, then watch the fireworks. Have Mortal Blast copy Mouch's strike if you're starved for arithmetica, Shining Crush otherwise. Without lucking into your original Mortal Blast, that's 3 Mortal Blasts for 1 total arith.
calm stump
fresh ocean
