>>16321656In BW3 there is an event early on in the game where you obtain a special Eevee. This Eevee evolves at level 25 into Eve (base form). From there you have two choices, the popular choice of upgrading to Eve's second form with the "Orb Bracelet", then to the third form with the "Orb Necklace" and then finally evolving it into the final stage "Infiniteon". Or you can use a "Death Stone" and evolve your Eve base form into the ghost Eeveelution "Limbeon".
What makes Eve so special is that the orbs it collects in it's 2nd and 3rd form allow it to form change into the 8 official eeveelutions. What's different is they are now forms which means you can change back to Eve and into another form as many times as you like. The trick is that even though you have 9 forms at your disposal, they each have their own moveset so it makes it tricky figuring out what moves you want Eve to learn as you play.
Oh and yes, it is based on Okami; and Eve is a Normal type in case you were wondering.