Ok I have followed Dasan to the place where 3 of him go to different corridors. I have been to each one: 1 leads to cliff / death, 1 leads to lower level where 3 walls are pushed but lead to nowhere, & 1 that leads to a mirror where he speaks to you. What do I do now?
Thanks for your help.

Yavin Final [0 Secrets]
>>Current Force Powers: all at level 3
>>Force Upgrade: None (you've got everything...)
>>Objectives: Defeat the dark Jedi Desann.

You start at the top of a long ramp... down it and up on the ledges for
items. Slash your way through the rocks blocking the passage (actually, Saber
Throw... they seem to explode a little)... in the next room rocks will be
falling on you, so watch out - even though they appear to be mostly illusory,
they can do a little damage. Up on the ledge and through the broken wall... to
your left the hall appears to end, though if you look closely you'll see that
the wall appears to be moving slightly. That's the way you want to go (through
that wall), but first head to the right for a pair of Small Shield Boosters.
Through the illusion wall and up the ramp... at the top is a hall with
flame pedestals on either side; they can damage you, so use PUSH on each one to
shut it off temporarily. At the end of the hall you'll get a short cutscene with
three apparent Desann's... "Your efforts are in vain."
The right opening leads to a death pit (when you go through the wall),
straight ahead is just a mirror where Desann taunts you, but left is the way to
go. At the top of the ramp is a pipe in the ceiling; cut that to douse the fire
at the bottom (you can't jump over or otherwise get through the flames, no
matter what) and drop down the hole. Down in the pit you'll have four short
corridors... the one to your back is blank, but the other three have Force Push
symbols on them. Use PUSH on the one in front of you, and go down the new
corridor revealed - down near the bottom of the wall on your left is another
Force symbol... PUSH that; the corridor that was blank is now pushed back.
Use SPEED down this corridor (with the traditional Jedi phrase, "I've
got a bad feeling about this.") to avoid the moving walls - I've found that the
best way to make a clean run is to wait until there's enough of a gap in the
first moving wall, hit SPEED, and run through, dodging and weaving. Just as soon
as you're past the last moving wall, stop and get your mana back, as well as
heal up and otherwise ready yourself... because dinosaur breath is next.
Cutscene with Desann (cheesy, hokey, totally Star Wars...)
That beam in the middle of the room gives a Jedi *temporary*
invincibility... activate it by PULLing on the two symbols on the upper level
(one on either side), then jump through the beam. After you've PULLed the
stones, the beam will stay on for the rest of the level, running through a
regular cycle. Hit SPEED at the middle of the ramp and attack Desann.
He's not easy, obviously... he can use any Force power (at their maximum
levels), and he can change saber styles in the wink of an eye. Do a lot of
Quicksaving during the fight... if you manage to damage him, Quicksave and
continue.
LIGHTNING works fairly well on Desann, if you have the Force power
left... but note that if you zap him, he'll zap you right back - it's best to
stick with the simple stuff like PUSH and SPEED.
If you use SPEED too close to Desann, he'll respond with Speed of his
own... if you trigger SPEED while still on the upper level (while he's below),
he won't notice it and he won't use his own. Also, when he throws his saber at
you, hit SPEED... he'll be temporarily defenseless, leaving him wide open to
your strikes. GRIP does not work... he can Push right out of it, but oddly
enough PUSH works sometimes ("You dare to Push me?").
Note that you can use your Lightsaber to chop at the base of any of the
columns in the room, and get it to fall - if you're careful (and very lucky),
you might crush Desann with a falling column.
Actually, I found Jerec (the main Dark Jedi in "Jedi Knight: Dark Forces
II") to be much tougher and harder to beat than Desann... but Desann is much
more fun.
One way I've found of defeating Desann easily (on the lower difficulty
levels): go down the ramp, and in the middle of it (that small level area) hit
SPEED... race down and just before you get to the bottom of the ramp, hit JUMP
as hard as you can - as you sail through the air towards Desann, aim at him and
use PUSH. As soon as you land, hack & slash... you should kill him with just a
few swings.
Once Desann dies (I kept expecting his hand to start twitching as Kyle
leaves) you get the usual semi-cheesy cutscene, and the credits roll...

Thank you dtriniman!!!!!!!!!!

Glad to help. (again ;)) Now play it over on Jedi Master and then get Jedi Academy.