This mechanic represents Sins various regenerative capabilities, the creation of Sinspawn, and also shows the mysterious cycle that the people of Spira are trapped in
The first was in the last maindeck slot, which was a Gutterbones
There are three primary ways to win with tokens: You attack with enough creature tokens that your opponent cant possibly hope to block them all, You pair your token generation with Mirkwood Bats, Impact Tremors, Zulaport Cutthroat, and similar effects that drain your opponents life total as your tokens enter and leave the battlefield, or You have sacrifice outlets that let you cash in tokens to kill blockers and/or drain your opponents life, like Goblin Bombardment
It ETBs with energy, sure, but it can convert energy to creatures without tapping, which, of course, means you can generate infinite tokens pretty easily with the other cards here