NFT fighters are obtained through NFT sales, the Karmaverse Marketplace, or from curing zombies in the Biolab using other NFT fighters.
Non-NFT fighters are obtained from supply drops, from the in-game store, or from curing zombies in the Biolab using non-NFT fighters.
Possessing and using NFT fighters in-game confers a number of bonuses; with at least 3 NFT fighters, you will be obtained to obtain serum and other rare token drops immediately, and farm tokens to earn money efficiently in every game mode. In addition, the more NFT fighters you possess, the better your drops will be, represented by Magic Find.
With non-NFT fighters, you may still play all game modes, but you will be either unable to obtain many token rewards, or have other limitations on drops.