Now, there's information to suggest that this only episode exists in two forms, the unregistered shareware version and the registered version that supposedly has some extra content/allows to adventure further or something along those lines. Here's what people say about the registered first episode:
(source)aethra wrote:The first episode was released in 1994 (v1.1 in January 1995): The shareware edition was distributed for free and presented the first 1/3rd of the storyline. If you wanted to play the entire game, you could buy the registered edition (for $25) and finish the complete first episode.
(I would pay $25 without hesitation, but the original developer's contact information is lost in the fog-of-time).
What's more, I've also encountered rumours that at some point, the author of Aethra Chronicles, Michael Lawrence, had released the full registered first episode as freeware via his website, but it had long since been taken down:
(source)wvn897s9b77 wrote:This game was released as freeware by the author (Mike Lawrence) on his own website. The page no longer exists, but I own a copy of the full game somewhere, downloaded from that site. I was looking for his other game "Dungeons of Kairn", but I only found a slightly more updated shareware version that fixed some bugs (like the one that allowed characters to carry more than two weapons).
The site was a obscure one, I only found him through some old MTG judge archives (dating back from around 1998).
This is quite hard to verify because archive.org only has select snapshots of the sire from that time, and none of them seems to be from the period when the game was distributed (provided that the info on that is not a hoax).
The same user elaborates further:
(source)wvn897s9b77 wrote:It was a long time ago, but as far as I remember, it was hosted at Earthlink.net. I've tried google cache, Earthlink and webarchive, but couldn't find it again. It took me years to find the site. The author, Mike Lawrence (Mike L.) used to be a Magic: The gathering judge around 1997-1998 (at the time of release of the Visions expansion set) and he participated in some old mailing lists of rules/judges. I think WotC has the archives stored somewhere. He had the link to his website on his signature, or maybe he only had his old e-mail account?
At any rate, the shareware version is available for download:
Shareware v1.0: AETHRA.ZIP
Shareware v1.1: AETHR11A.ZIP, AETHR11B.ZIP
Patch: APATCH.ZIP [not sure what it does, but it's not and update from v1.0 to v1.1]
Before Aethra Chronicles, Michael Lawrence released another role-playing game, called The Dungeons of Kairn, which is also available as shareware: KAIRN12.ZIP [v1.2]
[Edit] The freeware status of Aethra Chronicles is also discussed at the VOGONS Forums, apparently by the same user as I quoted above, but with some other details.
[Edit2] Review of the shareware version