>>2317616Red due to the power extender installed in Rouge, no technical/expanded explanation given.
>>2317629Presumably, a stronger defense means it draws more power from the battery.
>>2317668That was the Sword Impulse, not the Strike. The Strike didn't have any varying colours for either of it's striker packs. It's been guessed that the Impulse's VPS (variable phase shift) changes colours based on the defense's strength. Red VPS is said to be the strongest defense possible, for a melee suit that might have to endure a lot of fire for rushing straight into the enemy. Blue is a sort of a middle ground for VPS strength, and green could be the weakest.