NFT is the shell for our Soulmates, and the shells were split in 5 categories: Common, Uncommon, Rare, Unique, Legendary.
Rarity depends on genetics Soulmate has. If your Soulmate has at least one gene of, say, Rare category, he joins the category of Rare soulmates.
Starting attributes of bunny depend on category and genetics. Each time you level up your bunny, you can get 2 extra attributes points to distribute for Common category, 4 for Uncommon, 4 for Rare etc.