Exploud

The loudest Pokémon ever, or so far. He doesn't have a huge role on Twitter, yet. Exploud sometimes speaks loudly just because of habit. He monitors what he says carefully and will only say something incorrectly for special effect.

History
Exploud's former trainer caught him as a Whismur as he was passing through Rusturf Tunnel. This trainer was an aspiring Pokémon Master, as many young trainers were at that time. He trained and battled and eventually the Whismur evolved into a Loudred as the trainer continued on his journey. Sadly, however, as Loudred neared the final challenge of the Elite Four, his trainer released him in the final cave in Ever Grande City at the fragile pre-final-evolution level of 39. The reason why is not known.

Lost and confused in the cave, Loudred wandered aimlessly for months on end and not until a year later did he relocate the entrance to the cave. To his dismay, Loudred found himself at the top of a huge waterfall. Terrified at the thought of returning to the cave and seeing only one other option, Loudred lept off of the top of the waterfall and was immmersed in the cold water below. He could not withstand the raging torrents of water and after too short of a time fell into unconsciousness.

When he awoke, he could see that he was atop a huge rock formation filled with water. Confused, Loudred sat up quickly and was startled to see that he was not alone. Sitting not five feet away was a Swampert. Swampert had saved him from drowning and Surfed him all the way to his current location, which he later learned was Sootopolis City. The Swampert had always been wild, even since he was a Mudkip, and he was savvy with the ways of the world. Loudred decided to accompany Swampert in his travels and learn everything he could.

To make a long story short, the Loudred evolved into Exploud in his travels and, with his new knowledge of the world, parted with Swampert and returned to his home in Rusturf Tunnel. He hasn't seen Swampert since...

Twitter
When he first returned to Rusturf Tunnel, Exploud found broken pieces of metal and wires among other things strewn about the tunnel. Having no other hobbies, Exploud started tinkering with the pieces and after awhile his gained intuitiveness paid off. He discovered that some of the pieces fit together and after a while he assembled a fully functional Pokégear that had appeared from who knows where. With it he could access the Internet and, in turn, Twitter.

Expertise
Exploud knows a variety of physical and sound-based moves. He also knows much about the Sinnoh and Hoenn regions, having traveled through them for many years. But he has never been to Kanto or Johto.