Overview
Units are Equipment used by the Player primarily to increase defensive stats such as 
S-Def, 
R-Def, 
T-Def, etc., although certain Units do have inherent offensive stats in them. There are four types of Units currently in-game: 
Rear Unit, 
Arm Unit, 
Leg Unit, and 
Sub Unit. In addition to this, pairing up or having a set of a Unit and/or Weapon Series can give additional stats called Set Bonus.
Player Damage Resistances
There are about four categories of resistance in-game: Striking, Ranged, Technique, and Elemental Resistance, which compromises of the six Elements; Fire, Ice, Wind, Lightning, Light, Dark Resistances. Although, it if common to assume that attacks can be a hybrid, that of which can be Striking and Elemental, the game only takes one type into consideration for the computation in regards to resistances.
Damage Received Mechanics
Rear Unit List
Arm Unit List
Leg Unit List
Sub Unit List