Ill give this a shot. I usually try to use Treevil anytime mana speed is increased.
Wouldnt Treevil and Grimm using defense down override each other? Am I just using Grimm since he is my best blue option? Also, should DD heroes be on the left, so swap grimm and orla?
They will override but both reduce defense by 34% so it doesn’t matter that much.
Yes, Grimm is your best blue option but at the same time you don’t have any other unused hero that would be better than Grimm in other colors, qith costume bonus he can do a lot of damage.
You can try Grimm, C Colen (or Colen, which is the higher level hero, but C Colen is preferred), C Rigard (or Rigard if he is 4/75 fully emblemed on defence path), Ptolemy, Gullin for any war which war condition is not bloody. You need to pay attention to troops too. Tank may need Crit troops at Lvl 11 or higher. Ptolemy will need mana troops at Lvl 11 or higher.
You can switch out Colen when you have Octos at 4/80.
Octos and Ariel would be prority upgrade. If you have Octos and Ariel, then: