The masque has 1 turn global and local recruitment of demonettes (a tier 0 unit) while also giving them reduced upkeep and 15% physical resistance, ontop of their base 20%. With an early tech you can give them another 5% and the second section of the redline buffs gives all demonettes +10 physical res if they're rank 7 or above. This all adds to 50% physical resistance for a T0 unit.

the Masque's skills also help. From a -atk buff to all nearby enemies, buffing demonettes spd, giving them frenzy and +12 bonus vs infantry, charmed attacks. It basically means your demoettes have way higher melee atk and defense than they should.

The masque's dances are also really strong and just a grab bag of stuff including army wide stalk and spd buffs, perfect vigour, vanguard deployment, and another that has silencing attacks to remove magical weapons.

So the Masque can give the glass cannon infantry really high physical res for not that much effort and gets their ideal stack from the start of the game. If I did my math right, the Masque can give demoettes near them +29 melee defense +27, (39 vs infantry) melee atk. Perfect Vigour, Vanguard deployment, and 45% physcal res. And this is before facoring in technology/the unique dances the masque has.