There are six different "colors" of borgs:
Normal borgs are the most common, followed by alternate borgs, then clear, then silver, then gold, then black. The color of a borg can be determined by looking next to their name in the box. If their name has no cube next to it, the borg is normal. The other colors have specific cubes associated with them:
- Alternate: Yellow, red, and green cube
- Clear: Blue cube
- Silver: Silver cube
- Gold: Gold cube
- Black: Black cube
For the purposes of determining how much HP and ammo a borg has, its color effectively changes its level:
- Normal and alternate borgs have no change.
- Clear borgs have two levels less than normal.
- Silver borgs have four levels more than normal.
- Gold borgs have six levels more than normal.
- Black borgs have two levels more than normal.
Rare-colored borgs, i.e. borgs of any color other than normal, only appear under certain circumstances:
- The borg cannot be present at the beginning of a battle.
- The borg cannot be controlled by a commander.
- There are a few exceptions to this rule. If a commander appears in the middle of a battle, like Sho in "Retake Serenity Street," their first borg can be rare-colored. Also, Orochi can control rare-colored borgs in "The Decisive Battle: Defeat the Cosmic Dragon" at Sky Fortress.
If you encounter a rare-colored borg in a battle, there is a chance that you will get a crystal for it. As with normal borgs, you must collect all the crystals for a rare-colored borg to obtain the borg. For example, if you want an alternate borg that requires two crystals, you must collect an alternate A crystal and an alternate B crystal.
Not all borgs have alternate versions. See the list of all such borgs.