Ein (アイン Ain?) is a Pembroke Welsh Corgi and "data dog," meaning that his intelligence was greatly enhanced by a research facility. What exactly was done to him was not widely known. Ein became part of the Bebop crew and was a good friend of Edward.
Recessional of the Red Dragons[]
He was first seen at Abel City on Earth when he visited with Edward and her family; he was taken in by Macintire and Appeldelhi after Edward managed to find them after the events of Hard Luck Woman.

Ein beside Edward as they watched the war on Mars
Trudy was ecstatic to see him again, especially during a dire time of the upcoming war on Mars. Although he did grow agitated once he noticed Victoria's cat, Zeros. Even when they had to share Zero's Shuttle on their way to the war-torn red planet. Ein stayed at Annie's devastated outlet with Jet, Edward, Macintire and Appeldelhi during the fight. Before that though, he sniffed out an intruder, realizing it was Spike! Jet gave chase, till he was brought in. Ein then sniffed out another intruder, who was Kim Yokushimo, and was shielded and taken away by Macintire, while Appeldelhi managed to shoot him sparing Jet. Ein still functioned as a guard dog looking over the group, even Spike, till there was a newsbreak the Syndicate surrendered!
Ein then decided to board Victoria's truck and was escorted back to Earth with Edward and her family. Although Trudy would miss the cute pooch dearly.