If this is the only card in your hand, you can Normal Summon it without Tributing.
|Level-up reward||Yami Yugi level 35 [SR]|
EX Jewel shop
Swift Gaia the Fierce Knight has a great synergy with Wonder Balloons. Send cards from your hand to the Graveyard until Swift Gaia the Fierce Knight is left. By doing this, you can reduce your opponent's monsters attack and you can use Swift Gaia the Fierce Knight's effect which is you can normal summon it without any tributes.
Flash Assailant is a good monster to be partnered with Swift Gaia the Fierce Knight, since it can obtain its maximum attack and defense by having no cards in hand.
Currently, we can only obtain 1 copy of Swift Gaia the Fierce Knight which makes it hard to draw. By using Gateway to Chaos, you can easily search it from your deck and add it to your hand.