Okay, im not sure if there have been any questions about the DT (Damage Threshold)
Well DT comes from buffs or armor, and what DT does is help you take less damage than you normally would.

Now the way DT factors in with battle is that whatever the enemies final damage outcome is, you subtract it by the # of DT you have.

example: Your DT: 50
Enemy Final Outcome for Damage: 150
150-50= 100
Enemy New Damage is 100 instead of 150