Giga form is when a destructive robot similar to Gaia named JE6662-GU4 or "Giga" for short. Fuses with a Kamen rider with a black heart. to form "Giga Kamen rider"
Giga Nega Den-OEdit
Giga Nega Den-O is when Giga fuses with a Rider pass giving it a gripe and turning it into a weapon. Because the Saber on Giga has no mass it can be used as a whip. This form also alows Nega Den-O to pass through solid objects.
Giga Glaive is when Giga fuses with Glaives Sword. Giving him acces to use Wild card. andgives him the ability to multiply himself by 10 but then each one of him gets half of his power. Cards:
♠2 Slash, ♠6 Thunder, ♠10 Time, ♠A Change,
♦2 Bullet, ♦6 Fire, ♦10 Theif, ♦A Change,
♣2 Stab, ♣6 Blizzard, ♣10 Remote, ♣A Change,
♥2 Spirit, ♥6 Tornado, ♥10 Shuffle, ♥A Change,
Mighty Gravity, Mighty Impact, Mighty Ray,
Giga G3 is when Giga attaches to G3's Gun. Increasing himself by 70% and letting him double his gun to a sword. This lets him override Electric equipment.