You can Normal Summon this card without Tributing. If this card is Normal Summoned without Tributing, its original ATK becomes 1900. If this card is Tributed: You can add 1 "Black Luster Soldier" monster from your Deck to your hand. You can only use this effect of "Charging Gaia the Fierce Knight" once per turn.
When Charging Gaia the Fierce Knight is Normal summoned he still stays as a level-7 monster. So use him alongside level-1 Tuners to summon level-8 Synchro monsters. Some of these monster will need additional conditions like with Vylon Epsilon must use a LIGHT Tuner. Fabled Valkyrus requires a Fabled Tuner, like The Fabled Chawa or The Fabled Peggulsus, be used.