BB-8

BB-8 was an R2 BB unit droid owned by Poe Dameron. He held part of the map to Luke Skywalker, which is why he was so important, and caused many battles between the Resistance and the First Order. He was rescued from a scavenger named Teedo and taken in by Rey. After the destruction of the First Order's superweapon, Starkiller Base, BB8 came to D'Qar, where the droid R2-D2 had been in standby since Luke's disappearance, awoke. R2-D2 had the remaining piece of the map, and they put it together, showing the Resistance where to find Luke.