Help fleshing out a githyanki

I was going over my characters, trying to flesh some out before posting anything, and I came up over one I had never used.

(the guy on the left, who someone told me reminded him of Chris Redfield)

Well, I wanted this guy to be first an interplanar arms dealer, then I preferred a pirate. The problems swiftly arose:
-He´s 19th level. And githyanki. How could he circumvent the lich-queen´s taste in souls?
I had planned, perhaps, that the queen has no means of discovering her subjects´ HD... then there came Detect Law/Detect Evil (which reports him as moderate, 11-25 HD). The only way to circumvent those things against a CL 28 critter is having no such alignment component... but being Lawful Evil defines him! I´m trying to stop being a munchkin, so I won´t give him an alignment that makes him more powerful. (And having access to "Mind Blank" also qualifies as "he´s gotta be ripe for the queen", even if accessed from the Illithid Slayer class.)
So the only means I´ve found are, he must´ve been born outside of Tu´Narath, never got into the records as a citizen, and NEVER EVER came into Tu´Narath, lest he gets recorded, and unwittingly submits to being soul-eaten.
In any case, he needs some good reason to do that. Nobody´s entitled to know what happens to githyanki when they take their 12th level (and nobody metagames except the queen, it seems!), so I was perhaps thinking of fleshing him out with a riper past.
So been thinking... How about him, believing he is the heir to another branch of the royal family (it doesn´t matter whether Vlaakith and predecessors have done a good job in eliminating competition, he believes it to be true), and thus be amassing a force, planning to eventually assault and destroy Vlaakith, although not in order to replace her (he´s aware he´s all too piratey to ever be a king), but simply because of a despisal against tyranny he has, given he feels his birthright has been denied by someone who is nothing but a stopper on githyanki society (although he´d never fit in anyway; what do you call people who just barge in thinking they can take decisions for a whole nation based on a half-obscure clue they never bothered to really check?).
That makes him CHAOTIC evil (and I love that!), or perhaps merely chaotic neutral, I don´t know. This guy is supposed to be like the desert subraces from UA, being aware that evil people soon runs out of friends unless they have some method of keeping them in check. And he´s learnt to value friendship... because it´s somewhat more reliable than substitutes (except mindless constructs, but he´s a martially oriented character).
Basically he values friendship, because it´s easier to trace a planes-wide conspiracy with magic, specially when it incorporates chillions of weak links, leaves lots of traces and involves lots of people, than it is to trace a like-minded group of individuals who stay together. Basically he values friendship because it doesn´t show, although he´s not everyone´s friend, not by a long shot. He still keeps most people in check with contracts, curses, and others (That reduces him from chaotic to neutral evil... but it´s fine for me).
And then I had been thinking. His planar arms dealing biz... could perhaps relate him to one of the Golden Lords of Sigil, Spiral Hal... I think his name was. Strangely, I could find no information at all on Spiral Hal within the PW campaign setting.
Finally I came to learn that the queen´s already dead. So my HD problem is solved! But now I don´t know what to do of him... Has it already been decided how did the queen die? I don´t mean to bump in, but this guy had loths of plans (pun intended, but unrelated... as far as one can be unrelated to them, being it that they have their hands in everything except the Far Realms and then some).