While it wasn't entirely faithful to the behavior of Ygorl (I'm just going to assume he was pissed off for being magically imprisoned for a century, and faked his 'death' at the end so the heroes would leave him alone), the game Demonstone will have to be considered for this part of the Planescape setting.
Why? Because by the end of the game, the heroes wind up with the Silver Sword weilded by Gith herself. With the fragmentation of the Githyanki race following Vlaakith's death, this would become even more important. The faction that gets their hands on the Sword would get a big advantage (and not just because it's a powerful artifact). On the other hand, they have to pull it out of the grasp of a group of 3 level 19+ characters (probably level 20 or low epic levels, but at least level 19 because the sorceror knows two level 9 spells in the game), who will be ready and waiting for the githyanki to come. The fact that the characters have been granted a realm to govern (and will likely therefore have minions aiding them) would mean that it could be used as an adventure hook for lower-level PCs.
Come on, this a topic worth at least some discussion. We're talking about the Silver Sword weilded by Gith herself, here.