Eevee is a pokemon from the original 150, and one of the most interesting believe it or not. Eevee is a worthless pokemon in battle, but is worth the catch. Why? Because Eevee is one of the few pokemon that has multiple evolutions. They all involve special conditions (like an elemental stone) and some of the newer evolutions for Eevee has led to some very powerful pokemon. Just hope you choose wisely.
Eevee's Japanese name is イーブイ (Iibui) which is the Japanese pronunciation of "EV" the first two letters in "evolution".