Name: Ash/Dr. Badass/Miles (Early scripts)
Actor: Chad Lindberg
First Appearance: Everybody Loves A Clown
Last Appearance: Dark Side of the Moon
Number of Episodes: 5
Powers: smartest person the Winchesters know, Fluent Enochian
We first meet Ash in season 2. Turns out he's more than just a drunk who sleeps on a pool table during the day... who knew, right? Being a genius who was kicked out of MIT and now works (and sleeps) at a roadhouse for hunters, can we get anyone else more badass?
While Dean compares him to Lynyrd Skynyrd in Everbody loves a clown, Ash calls him a genius. He can take John's research on the Yellow-Eyed demon, put it to what looks like a homemade laptop, which sets up a "Demon Alert System" to track down associated appearances.
In Simon Said, Ash helps track down a bus logo from Sam's vision.
In Hunted, he is able to find children who are 23 and whose mothers died in a house fire. This leads to finding about the death of another one of the "special kids", but who else could come up with this stuff besides Ash?
In All Hell Breaks Loose pt. 1, we have some information that Ash will only tell Dean in person because he doesn't want anyone to find out. Unfortunately, by the time Dean gets there, the roadhouse is blown up, along with all the hunters and Ash in there... RIP...
But nope, the awesome writers decided to bring Ash back for another episode! Three seasons later in Dark Side of the Moon, the boys get shot up to heaven, only to be chased by angels and find a masked wrestler who wants them to follow him. But guess again, it's the one and only Ash and his 'blue heaven', especially since he was his "congregation's number one snake handler.
It turns out that this isn't the first time our boys have seen Ash since he was killed. Remember all those times Dean died in season 3? All the other times the boys have died? Yah, they keep dying and he keeps finding them. Of course, with his new homemade laptop (or is it the same one from season 2 that got sent up with him?), we find out that he's fluent in Enochian and has been able to tap into heaven to travel places using a practical application of the string theory. He has been able to meet people like Einstein, Johny Cache, Malanega Vatsyayana, and many others, which do not include Ellen, Jo, or Marry and John.
The only thing that upsets Ash is the fact that Ellen and Jo are dead. He does, however, have an awesome friend in heaven, who turns out to be Pamela, eyes and all. He, of course, is cool with getting killed and helps the boys get to the garden.