Jenx fled from the kenku homeland (somewhere east of Marakeel) when it was invaded by ogre magi, rescuing some eggs on his way out. When he reached C-Ra, an innkeeper stole the eggs, and Jenx was unable to recover them. The innkeeper turned out be an old and crafty dop who goes by the name Kambhyr; he's still in the C-Ra area, he hates elves (he apparently escaped from some high elves in the dop smuggling trade before coming to C-Ra), and he's the uncle of another extremely slimy dop of our acquiantance called Kareelmola. Based on the timing, these eggs are probably the ones that found their way into House Baleel's hands.
Jenx has been acquainted with the Red Mage (formerly known as Thayo) for some time. Though Jenx has a lot of trouble tracking time (even his attempts to order events are suspect, though I'll mostly go with his ordering here), the following incidents are part of their shared history.
Sometime in the past, Jenx and Thayo took a trip to the desert volcano looking for a way to boost their mage abilities. They tried playing with a brass idol to get wishes; the catch turned out to be that the wishmaker had to answer several questions correctly or their wish would be perverted. (These wishes may or may not have involved the efreet Ganeth fought at the volcano during Silvana's first challenge as Champion of Good.) Jenx missed one and went insane -- when he was asleep, he would sometimes go off and commit crimes (usually burglaries). These states usually last only a few hours, but once he had one last for two weeks; he also once went adventuring in that state. He usually remembers pieces of what happened during these times as dreams. From what he can recall, his thefts usually involved objects set with red gems (including a ring that was being worn when he stole it), and he always ended up giving the objects to beggars who happened by (though these thefts were often in areas where one wouldn't expect to find beggars).
Jenx also has odd dreams after drinking Zipquaff, a potable provided by the Red Mage, where he dreams that he's a huge winged demon from the Abyss (reminiscent of a Dreamspace persona). He doesn't remember having any Zipquaff dreams while he was insane.
Thayo and Jenx once took an adventuring party to the Zim Pits (the lair of the most ancient red dragon, somewhere in the mountains north of C-Ra; rumor has it that the Zim dragon is amused by the adventurers who come to plunder his lair, which is stocked with humanoids near the surface and red dragons farther down). The other members of this party were:
Somewhere along the line, Jenx and the Red Mage had a duel that involved drinking Zipquaff and diving out of clouds; Jenx doesn't remember the reason for the duel but notes that the Red Mage has a habit of manipulating memories. That night (which had a new moon), Jenx had a Zipquaff dream where he went off to see a "broker of power" who bears a definite resemblance to Zzukiss' Dreamspace manifestation. (A second, similar critter was there as well; if the broker was Zzukiss, this was probably Zzukist. Jenx was in his demonic form, standard for a Zipquaff dream.) The broker said something about playing a game, and at some point Jenx saw some islands and a solar eclipse. (This could have taken place at the about the time the party was caught up in the Dragon Tears Islands game, which climaxed during a solar eclipse, but with Jenx's messed-up time sense it's hard to know.) Jenx was convinced this was an experience brought on by too much Zipquaff and was mostly trying to wake up (or attacking Zzukiss, at one point) rather than listening. He also had a showdown with himself at the end (much like G's run-in with "Dark Iceman") that he barely survived. Jenx says that time seems to be especially messed up around this experience.
For what it's worth, Jenx's color is Yellow, though Red seems to be his favorite. (Silvana notes that yellow seems to be strongly associated with songbirds.)
The Red Mage got Jenx to try cracking the Nirduk Vault on a bet (after getting him full of Zipquaff first). Jenx failed, but the Red Mage pulled him out just before a trap on the door would have fried him. He thinks the trap involved a combination of death and insanity (and that if he hadn't been Zipquaffed he'd have been driven insane by the experience), and the trap seemed intact when he left.
Jenx and Scumwort were recruited by the Red Mage to combat the "Spider Infestation"; together they went through a dungeon and took out a Spider Monk base, complete with dreadnought. Jenx snuck up on the Mr. B and dealt it the killing blow from behind, and Scumwort dubbed him "Spiderslayer" more or less as a joke. Since then, he's been trying to undermine spider operations, including what he fears may be a revival of the Spider Monks. Most of the monks he's seen have been novices with only basic training and red d8s (though one of his scouts reported seeing a pink one; fortunately, no dodecs have been spotted so far), but he's heard that there's an old grandmaster out there somewhere. He believes that the Spider Monks are recruiting in the East as well as in C-Ra; they're also recruiting for assassins to be used in the war (possibly against adventurers who try to take on the spiders in Silverton).
Jenx has lost his racial abilities after straying from the Path (about which he says only that it's a "kenku thing"), but he provided some information about recognizing a dop when reading its mind: He says it, "feels like sticking your beak into an anemone. A young dop's mind is hungry. Older dops are better at hiding it." He also warns that older dops can detect mental probes, though young ones can't, and notes that dops are especially vulnerable to psionics.
Jenx was last seen in the Cloudlands during the strike on the Pazazu ship and was presumably responsible for the implosion of their ship's central gate. Though the gate reappeared on the Elemental Plane of Ice, Jenx's whereabouts are unknown.