Gem-Knights (Comments Or Comcerns)

Monsters
Gem-Knight Crystal
Gem-Knight Garnet x3
Gem-Knight Sapphire x3
Gem-Knight Tourmaline x3
Elemental Hero Prisma
Gem-Armadillo
Gem-Knight Alexandrite x2
Gem-Knight Emerald x2
Gem-Turtle x2
Gorz the Emissary of Darkness

Extra Deck
Elemental Hero Gaia
Evil Hero Dark Gaia
Gem-Knight Aquamarine x2
Gem-Knight Citrine x2
Gem-Knight Prism Aura X3
Gem-Knight Ruby x3
Gem-Knight Topaz x3

Magic
Burden of the Mighty x2
D.D.R. - Different Dimension Reincarnation x2
Dark Calling
Dark Factory of Mass Production x2
Dark Hole
Fusion Gate
Fusion Weapon x2
Future Fusion
Gem-Knight Fusion x2
Mystical Space Typhoon x2
Swords of Revealing Light

Traps
Common Charity
Mirror Force
Pyroxene Fusion
Return from the Different Dimension
Solemn Warning
Torrential Tribute

Gem-Knight =/= Hero Gate. Gems fuse normally with GKF. Run 2 Tourmaline, Sapphire and Garnet. Run also triple Turtle and Armadillo. One or two Obsidians, Alexandrites and Ambers will fit the theme. To finish the deck place Thunder(3 Thunder Dragon/maybe a Rai-Oh), Pyro (3 Volcanic Shell/maybe a Gaia Soul) and maybe Aqua monsters(namely Treeborn Frog and Mobius). Citrine, Aquamarine, Zirconia and Prism Aura wanna be your main fusion monsters. Aura pops, Aquamarine bounces, Citrine attacks, Zirconia finish. Master Dia is also viable, and run 1 copy of each other Gem-Knight fusion monster(2 Amethys if running Treeborn). Don't run s/t other than staple and FF/GKF.

About Dark Gaia, try use cards to discard/send monsters like Caius to grave(treeborn fits well here) and then use Calling, Return from DD, Release from Stone to cycle from RFG Zone to field to grave to RFG Zone, like Psychics.

Thanks duellogs! xD