Iris first encountered Drilbur one day when she was still living in the Dragon Village and a Minezumi she befriended had its nest stolen. It was Mogurew that stole the nest and
Iris attacked Mogurew but she ended up getting pummeled by it. Day after day,
Iris returned to challenge it and on her tenth try she managed to kick it away but it then got tangled in some vines off the side of a cliff.
Iris came to its rescue just as it began to fall. The two of them became friends from that day on.
The two began to participate in Pokémon battles together and they had one victory after another. Having gained confidence, they decided to partake in the annual battle tournament held in the Dragon Village. They retreated to the mountains to do harsh training. During a battle with a trainer and its Crimgan on the day of the battle tournament in the Dragon Village,
Iris' Drilbur evolved into
Iris' Excadrill.