Rolling for attacks...
Backstabs attacks!
Attack roll: 13 (+8) = 21
Dodge roll: 14 (+6) = 20
She hits!

Damage roll: 7 (+9) = 16 - 14 (DEF) = 2 + 2 = 4

Fighter B's at 29/45 HP.

I attack using lightning! The enemy's wearing metal armor, so, I have an advantage.
Attack rolls: 9, 13 (+7) = 20 (take the higher roll in this type of scenario)
Dodge roll: 5 (+6) = 11

I hit
Damage roll: 5 (+11) = 16 - 6 (metal armor is ignored in this case) = 10 damage
HP: 19/45

My MP: 2/8.