Ein is a Pembroke Welsh Corgi whose intelligence was greatly enhanced by a research facility. Ein is known as a "data dog." What exactly was done to increase his intelligence is unknown.
Abdul Hakim steals Ein from this facility and Spike Spiegel ends up with Ein while attempting to apprehend Hakim in Session 2: Stray Dog Strut. Ein remains a constant and important fixture in the Bebop cast up until (Session 24: Hard Luck Woman, in which he insists on staying with Ed when she leaves the Bebop. Ein is last seen living with Ed on Earth.
Despite Ein's enhanced intelligence, he remains incapable of speaking (other than barking). Because of this, his intelligence largely goes unnoticed. It does seem that Ed understands Ein through his body language and barking, however this is never made explicit. Ein also barks once for yes and twice for no.
Evidence of Ein's IntelligenceEdit
Throughout the series, there is Evidence that shows how intelligent Ein is.
Cowboy Bebop: Knockin' On Heaven's Door (The Movie)Edit
- Ein makes a well calculated move in shogi for Jet who is playing against Spike, who passes it off as a coincidence.
- Ein correctly predicts that Vincent is the culprit long before anyone else suspects him. Ein knowingly barks at a picture of Vincent that comes up on Ed's computer screen, and while Edward lets everyone know of Ein's thoughts, no one pays attention to her.
Stray Dog Strut (Session 2)Edit
- When Spike and Hakim are fighting on the bridge, Ein jumps down to the passing boat to escape.
- After Hakim jumps down to the boat, Ein jumps into Spike, leaving them in the water and Hakim stuck on the boat.
- When Hakim is escaping with Ein in the car, Ein jumps onto the steering wheel and pushes several buttons in an attempt to steer the car off course.
- At the end of Stray Dog Strut, Punch explains on Big Shot that Ein is a "data dog", meaning he was developed in an illegal lab and that "collectors would pay a fortune for it" on the black market, which the Bebop crew would not attempt.
Mushroom Samba (session 17)Edit
- After running into the dealer, Ein realizes the mushrooms are "bad mushrooms" and stops Ed from eating them by eating them himself.
- At the end of Mushroom Samba, while everyone is fighting on the train, Ein speaks with a cow telling it to stand in front of the train so it will stop. It isn't specifically shown what is said, but as Ed and Ein are leaving, Ein barks and the subtitles read "THANKS!". Then the cow moos and the subtitles read "OH, DON'T MENTION IT!"
Speak Like a Child (Session 18)Edit
- Ein answers Faye's incoming call on Ed's computer. Faye thinks nothing of it, and mumbles about wanting someone who can talk.
- In the preview for the next episode, Ein manages to speak its name, "Wild Horses". Spike hears this and is shocked, but seems to brush it off. Being a preview, it's likely this is not considered canonical.
Boogie Woogie Feng Shui (Session 21)
Ein figures out the intended use of the moonstone as a beacon to find Pao (or at least recognizes the Loupan's interaction with the stone).
Brain Scratch (Session 23)Edit
- In order to avoid having a human member of the Bebop crew be enlisted into the radical religious cult, S.C.R.A.T.C.H., Ein is put into the headgear that is used to link to the cult's website. Within seconds of being logged into their virtual lobby, Ein himself hacks into the underground portions of the site.
- All of Ein's vocalizations were done by a Cardigan Welsh Corgi named Jack, owned by the show's producer Kazuhiko Ikeguchi.
- Japanese voice actor: Kōichi Yamadera 
- Given the dog's highly intelligent nature, the name "Ein" is likely short for Einstein.
- The dog Zwei from the animation series RWBY is a reference to Ein.