In special world I was able to put together a unit that did 4 million damage in first round.......only did it once so far, but it almost always does 1million+ in first round.

Nidhogg - re-act 20/20, chiv stance+ 15/15, Hard Shell Press+ 15/15, Wisdom Spirit+ 15/15, ??
Support - fill with guards/muters

base int at lvl 99 + spirit gives hsp+ 184% activation
really high Intel boosts the def buff when he takes a hit, multiple def boosts increase hsp+ damage
round 1:
Nid casts re-act (self boosts Intel 10k-18k, depending on cmdr/support)
Casts hsp+ (not much damage)
other monsters go
takes 1-3 hits, def buffs 800K per hit (up to 2.4 million def boost)
Nid casts re-act again ( self buffs Intel ~130k)
Casts hsp+ again, this time does 3-4 million damage

the more hits he takes the more chivalry stance boosts his defense

even after he loses his guard/barriers after the first hsp+, he somehow still takes no damage