Finally, the Elan Heritage feat. I will paraphrase it here.
Basically, it's a feat you can only take at 1st level, and can't retrain out of (without a -real good- story about why) that grants the Immortal origin, for the purposes of effects that affect that origin, and Telepathy 5...similar to what Kalashtar have. They gain a racial power called Elan Resilience that gives them an interrupt that grants damage resistance equal to their intelligence modifier once per encounter. That increases by 3 each tier.
However, there are several other feats, at each tier, that key off of Elan Heritage as well, making it a 'gateway' feat. There's also a paragon path that keys off of it.
The fluff of elans is that they're humanoids who have undergone a process that destroys their biological bodies, and creates a new body composed entirely of psionically manifested matter. As such, any humanoid race can take the Elan Heritage feat.