Below are each character's contribution, and other links to the quest.

• Fahd Yazid - Fahd is the shaman who has been teaching Isadora the Rhiani Swift Stallion Tradition ways, and who has been leading her into the spirit world with his raven fetch. Also Fahd has lead them to some of the spirits of the dead who have filled in some of the gaps.
• Isadora - In part it's through Isadora's investigation of the spirit world that they've come to understand the history of Green Lake (above). This has laid the basic groundwork for the quest. Isadora also accidentally triggered the raising of the temple out of the lake, and has served as the point contact with the spirits inside since then. Together Isadora and Fahd have put together stations 4-6 and 10 and 12. Isadora will play the part of Terian, presumably.
• Okhfels - other information about the history has been discovered by Okhfels using the dome, and investigating the ruins. He will almost certainly play the part of Neorut in the quest. When he heard the story, he knew he was fated to it.
• Beliria - this Tethian woman has been instrumental in deciphering some of the runes left in the ruins, and how they relate to the quest. But just how honest has she been? Between Beliria and Okhfels, they've come up with the introductory 3 stations.
• Haikain Ai Julali - Haikain is an animist who has formed strong bonds with the lake spirits who originally were casting about for somebody to connect with after being awakened from their long imprisonment. Haikain has seen a vision that fills in stations 7-8 above, and related it to a few people.
• Egani - in understanding the portal creation rites described to him by the head, Egani may be the only person who can accomplish station 7. Further, the talking head may have some information regarding the nature of the sorcerer's interference in the ritual - she was, of course, in the fortress of madness when these events occured. Even more importanly, Egani can provide one of the honored births, and the ritual to bless the children for station 11. Important Note: As Chris says above, Egani holds a lot of keys, but he isn't going to participate, in all likelihood, unless somebody approaches him and offers him something. Who is going to deal with the Egani-devil to make this work?
• Orca - Is her child actually a demigod, and what affect will it's birth have on the quest? The timing of her pregnancy coming due, and the other portents leading to this quest happening simultaneously can't be co-incidence, can it? Will the child be offered in station 11?
• Belnif - Belnif has been doing some spirit world investigation on his own, and has come up with the key chant in station 9.
• Archelaus - Archelaus has a direct line to the sorcerer, and could, in theory, determine what it was that the sorcerer, or his agents, did to interfere with the ritual the first time. Keep in mind that Amestris, Archelaus' wife, may be key in motivating him. Of course, the sorcerer still expects that Archelaus is doing his bidding in all of this.
• Bird - he was there when this went down more than three millenia ago. What does he know about the event? What are his motives regarding it happening again?
• Artanis Aeldarundė - Artanis is stuck in the Spirit World under the city, not far from the ritual site. What will he give to be present at the quest? And what role will he play?
• Other Characters
  • Will Aysha be freed by Bird to play some role in the quest? As Bird's slave? As a slave to the master of the White Wood? Or as her own agent of chaos? Will Serama be able to control here destiny here, or continue to be enmeshed in the plans the sorcerer had that destroyed her father? Will Sebastian, dead, yet still lingering in this realm of the spirit world, play some role in the quest?
  • Will Elkaru, Fahja or Gennadi be finally joining with this Rhiani tribe, and helping out with the quest, or will they move on instead to some other? Gennadi has his sister back now - but where will they go, if they don't decide to stay and help out? Is this the last place to run for Elkaru? What will Fahja do in his poisoned existence; can the tribe accept such a taint?
  • Will Tamul become an honest man and do something for somebody other than himself? Can Rahkleth stand yet another battle, or can he find some more peaceful place to go? Are Nurek and Idris members here, and to they contribute to the quest? Or are they untrusted minority outsiders? Can Idris trade one worship for another? Can any of them?

The above are just the ideas that seem most obvious, there are many more subtle things at stake in this quest.

Uplink: Lake Heroquest