Don't have them fight to slay their captors. Just have them fight to get away. This is actually surprisingly plausible, against even very high level monsters -- they just don't do as much damage as you would expect. Against this particular captor, escape is virtually guaranteed. I mean, the Githyanki warrior only has a base speed of 5, and his main attack is melee. If the party splits up, he's catching at most one of them. If they run at top speed, he might not even catch that that one.
His main trick--the telekinetic grasp--is very nasty. His main attack has a damage expectation of 14 normally, but it goes up to 24.5 on an immobilized character. Normally, your characters will be able to take one solid hit from him and still get away. But after being immobilized, a crit or even just a lucky damage roll would drop them--and nothing stops him swinging again.
Note, however, that the telekinetic grasp is an
encounter power. He's getting at most one party member with that trick. At least three are getting away, and if they can defeat the power, all four are.
That's not as hard as it looks.
For starters, it's range 5, and the guy has a base speed of 5. The "scream and run" strategy will get them well out of range, and plus, if they resort to that you'll know they Properly Fear and Hate your villians.
Also, it's save ends, so anything that grants a save could break it early. If you have a Cleric with Sacred Flame, that could do it, though he'll need mooks to shoot at. By the way, there
are mooks in this fight, right?
Because no fight is un-fun if there are mooks to kill. I recommend grabbing the stats for the Goblin Cutter, reflavoring him as a . . . githyanki foreman/engineer or something. Lose Goblin Tactics, maybe giving him a point or two of psychic damage.
Also, that guy's defenses
look insurmountable, but they're not
actually insurmountable. A standard wizard is going to start out with an int bonus of +5, perhaps a little better if he's using a wand. Shooting at a reflex of 23, he needs to roll an 18 to hit. Yeah, thats a 15% chance--lousy--but the thing is, his foe has a speed of 5. In a big enough room, he can kite the guy all day with magic missile. The fighter's in a similar spot; he gets +5 from strength, +3 Proficiency, +1 FWT, for a total +9 to attack, and he's swinging at an AC of 28. He needs 19's. 10%. Ugly, since he probably only gets one swing before he has to run . . . but not
totally impossible. A little combat advantage here, a little
Lead the Attack there, the odd Dragonborn Fury or Action Surge . . . and the fight very quickly can go from 'impossible' to just plain ol' 'reasonably tough'. It just depends on how clever and capable your players are. You may find you need to even the odds a little. Then again, you may find that you don't.
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Here's how I'd run it:
Prologue, if you want one - Your PCs and about 3 NPCs of the same level are in the mines together. The guards are two githyanki warriors -- straight from the monster manual -- and three minion githyanki mining engineers. One of the NPCs decides that you can take the guards, and starts a rebellion. If the players join him, fine; if not, fine. Play out the fight, don't pull punches, roll on the table and muse out loud, "Oh, yeah, 28? Yeah, I guess that hits his fort . . . just barely. . . " If the players miraculously win (and don't count that out,
my players probably would . . .), great, if not, that's fine too. Probably nobody got killed outright, though a lot of people probably got dropped. Bring them back. Have the guards execute the rebellion's leader. Have a taskmaster ask if you shouldn't execute the whole lot, and the guard say, "Yeah, I would if we had a few more of their kind--as it is, I don't think they'll make that mistake again."
The point of this scene: Learn how those githyanki work up close and personal, see how hopeless it is to fight them, decide you hate the bad guys, build up some angst, etc.
Scene 1 - Your PCs and about 3 NPCs, mining in the mines. A critical event occurs -- a rockslide. Passageways open up in three directions. Klaxons go off. Two prisoners dive down a passageway and one of the githyanki guards follows. That leaves the PCs, one NPC, one guard, and three minions. If they think they can take him, let them try; make sure the NPC bites the dust fast as a warning, so they still have time to run. The expectation is that it turns into a running fight in the tunnels. If they manage to overpower the guard, let them exult for a moment . . . and then have two more show up, drawn by the klaxon. Have a long, skinny weaving tunnel with obstacles and tiny fights--rats and the like. Have that guard hot on their tails for three or four rounds, until they finally get to a quiet segment and can gain some distance.
Scene 2 - We need a morale booster by this point. They're running through the tunnels with a big nasty they can't take in hot pursuit. They happen upon a group of those engineers, maybe; maybe they're having a prisoner fight a giant rat for sport or something. They slaughter the bad guys easily, rescue the good guy. The place is defensible and concealable. Skill challenge -- thievery, dungeoneering, perhaps perception or stealth to make it look like the place was cut off during the cave in. Succeed and they hear their pursuer pass by. Take a breather.
- Pad with tunnel encounters / generic dungeon as desired -
Finale - My players would want to take down one of those guards by the end of the night, even if it wasn't in a fair fight. So let's do that. Say they get to the exit of the complex, and there's one guard waiting for them. He lost them in the tunnels, but he followed it to the end, since that's clearly where they're going. If the players want to take a healthy guard from scratch when they're well-prepared and rested, let them try; they can always push past him out the door of things go south. Alternatively, make it an unfair fight: have a higher level NPC (say, a nice self-sacrificing paladin) come along for the sole purpose of taking hits. Or have half a dozen other prisoners on the PC's side--run them like minions. They're also there just to take hits. Have the terrain favor ranged attacks. Give them a macguffin of githyanki slaying. Have a cave-in leave dust everywhere, leaving the guard blind for the fight. Have the original guard give up the chase, leaving just the junior guy who wants to impress his superiors (so knock a few levels off the original template).
It has the potential to be an awesome fight, but it requires reading the players' moods and capabilities right. It also has the potential to be very swingy, so make sure there are outs available--make sure running out the back door is always an option for the PCs, and make sure the
players know it's a valid one.
I'd also consider running the githyanki 4 or 5 levels down from where he is in the book. If you do that, the PCs become much more likely to win any of the encounters with him alone. This may be what you want. I'd go into the evening with the two stat blocks, and swap them out between encounters depending on how the PCs are doing.
The whole thing is dangerous -- I wouldn't run it if you don't have players that think quickly and tactically, and that like dangerous games. Running a monster that high level
is breaking a few rules; if you have players that will react to that sort of thing with 'sweet, a challenge' cries and evil grins, cool; if they'd react by whining or dying and blaming you, don't try it.
You can break the rules. 4E is surprisingly tolerent of it. Just be prepared to pick up the pieces.
