Dark Arena
Jeremy War
Beyond the ceremonial chambers of the Nali water God lurks the darker side of Nali history. This ancient and imposing structure is now used by the Skaarj as a torture house and detention centre for Nali natives and human crash victims alike... but within the structure something even worse lurks.

You start in the hole you jumped down at the end of The Ceremonial Chambers, and plunge into a pool of water beneath.
Climb out of the water and on to a small stone ledge. Follow it along and descend the ladder on the other side. There is a Health Pack under the ladder if you need it. As you proceed down the next corridor you will hear a splash and a familiar growl from behind you. No prizes for guessing what that is, so turn around and face the ladder. Use a good weapon and slaughter the SkaarjWarrior who has followed you in.
Follow the corridor round and you will see monk statues and a shut door with no visible means to open it. So, return to the corridor. Shoot the vase and barrel open but they reveal nothing.
The switch is actually one of the several carved face blocks on the corridor wall. If you stand in the corner of the corridor looking at the big doors, it is the one that faces you on the right. So, press it. Shortly the big doors will open. Step through, and the doors close behind you.
Descend the flight of steps beyond and collect two cans of 12 Eightballs from behind the light fixture at the bottom. Follow the stairs round to the left and walk along a short stretch of corridor, and the music will start as you emerge into a huge open area with tall cliffs.
The eerie wasteland out here contains the looming wall of a large structure in the middle - the dark arena. Head first around to the right until you reach the point where the curving wall of the arena meets the tall cliffs. There are Tarydium Shards and Nali Healing Fruit here.
Follow the curvature of the arena building round until you reach a grand flight of steps to two doors. This is the main entrance, bordered by torches and a flag on a high mast. A Nali is crucified high on the wall; put him out of his misery. If you can lob an Eightball grenade onto the roof of the arena, you may see a very odd message! :)
Don't go in just yet. Continue round the wasteland until you come to a patch of earth with four-armed crucifixes guarded by a SkaarjWaarior. Kill the SkaarjWarrior and the crucified Nali here, then collect the Nali Healing Fruit and Assault Vest in this area. Follow the fortress on round.
Eventually you will reach a dead Nali by a poorly repaired patch of the wall that has been broken open. Take the replacement Flashlight dropped by the unfortunate Nali, then read his diary.

"I escaped from my cell but can't find the strength to go on. Remember me to my family..."

That's it, time to deal with these damned Skaarj. Blast the weakened wall open with a secondary fire charged Dispersion Pistol, then descend the Nali's tunnel into his open cell. As you enter the evil building you will hear screams and cries; try your best to ignore them. Leave the open cell into the prison corridor, but be alert because there is a SkaarjScout on patrol in this area who will ambush you at some point.
The other cells here are currently locked. Take a left and go through a wooden door that is on your left after you go round a dark right-hand corner. Enter the room, where you will see steps leading up to a balcony where a lever controls a lift which is a shortcut up to the main arena. I strongly advise against taking this shortcut.
Kill the SkaarjWarrior guarding this room from the balcony, then leave the room back into the prison corridor. Find the corridor that crosses straight through the middle and follow it so that you come out on the opposite side of the prison corridor ring, where there are two more wooden doors. Take the door on the right and you will find a walkway going down to some cages over lava. Kill the SkaarjWarrior that runs up from below.
The middle cage has a Nali trapped in it. Sadly, there is nothing you can do to release it. If you are of a sadistic disposition then you can press the lever behind to ditch it into the lava, but I generally leave it to its prayer.
Return to the prison corridor and take the other door. Here, a SkaarjWarrior guards two switches on the wall and a Stinger on a table. Kill the Skaarjwarrior and collect the Stinger, plus Tarydium Shards from barrels in the corner. Press the two switches to open the prison cells.
Return to the prison corridor ring and explore the cells; I do this clockwise. Note: some of the cells might contain Tentacles on the ceiling. This is generated at random, so I can't tell you which. Just have your Automag at the ready.
Going clockwise: the first cell is the one you came in by. Nothing new to see. Opposite, a Nali stands in a typical catatonic state. Further along, the third cell contains bandages and a human corpse.

"I must try to find a way out of this place. The lizard men in charge here are strangely barbaric given the technological advancement implied by their weapons. It may be harder to fool them than I first thought, but I must make the attempt."

Looks like she failed. The opposite cell contains a clip and another human corpse.

"If I am to die in this place, it pleases my mind that some of my former captors are here with me. Tomorrow I will find my own peace in death knowing that they have all suffered before me."

She must have been a prisoner on the Vortex Rikers. Continuing clockwise to the other side of the prison corridor ring, the fifth cell contains yet another human corpse.

"I'm so hungry. I hope that the others in the scouting part from the ISV Kran will find me. This is the only hope that keeps me going from day to day. Without that to cling to I'd be insane by now. I can't stand the screams of pain much longer."

ISV Kran? A log mentioned that ship back at NyLeve's falls. Maybe you'll get to see it later. Anyway, continuing to the cell opposite, one more human corpse's log simply says:

"I wish I had died when the Vortex Rikers crashed. I do not know what is to become of me. I am scared."

The seventh cell contains another catatonic Nali and a useful Shield Belt. Opposite, the final cell contains Bandages and a dead Nali.

"The Skaarj have brought in a new batch of the two-armed softskins from another of their raids. I fear that one of them is the Messiah, come down from the heavens, but I must pray that I am mistaken and not give up hope for the freedom of my people."

More talk about the Messiah... anyway, that detour complete, return to the room where the two switches were (it should be the first door clockwise from here), and go through the door on the side wall. There is a flight of steps beyond, but before going up, open the crates in the shadow in the far corner to get a Health Pack and two Clips. Climb the steps and pass through the door at the top; you will be in the foyer inside the main entrance.
No need to go outside unless you left anything behind. There is a flight of steps here up to a landing above, or a lift to the same place as an alternative. First though, collect what you need of the Health Packs and Clips from the alcoves at the back of the room. Go to the pedestal by the steps and read the stone carving:

"The weak shall be struck down by the hand of the beast."

Sounds suitably ominous... anyway, go up the steps and step on to the landing at the top. Two SkaarjScouts will appear, one up here and one down below. Kill them both. (Note: if you kill the one that appears up above and then can't find the other one, it will have gone down the dungeon steps. Follow it and kill).
When both Skaarj are dead, doors off the landing will unlock. Return up the stairs and take the door that is to the left if you are facing the front doors.
The sweeping corridor beyond goes all the way round the arena and back to the landing at the other end. There are several doors turning off it that are locked; to open them you will have to kill the two SkaarjWarriors patrolling this corridor.
So, set off up the corridor and collect the Tarydium Shards from the base of the first pillar. Continuing, you will reach the first locked door up a few stairs on the left, either side of which is a Health Pack. Further up, another pillar has a couple of Clips nearby. You should meet the first SkaarjWarrior around this point, so kill it, but don't use up your Eightballs - you'll see why soon.
You will soon arrive at the next locked door on the left, with a smaller door opposite. You will quite likely meet the other SkaarjWarrior now, so kill that too. Once both SkaarjWarriors are dead, the smaller door opens, but first plunder the corridor for the rest of its supplies including Health Packs, two cans of 12 Eightballs, two clusters of 40 Tarydium Shards and two ASMD Cores.
Return to the smaller door that opened and enter the small antechamber. Here, three levers must be pressed to activate a mechanism to open the other locked doors.
Pass through and you will be on a viewing balcony over a large arena with a central pillar. This balcony is patrolled by a SkaarjWarrior; kill it but don't jump off yet. Visit both extreme ends of the balcony to get two ASMD Cores and two Health Packs. Save your game now!
That done, ready your Eightball Gun, drop down and collect the Eightball Gun that lies on the ground there. Things are about to get unpleasant: as you collect the Eightball Gun, the metal ring around the central pillar rises violently and the three sets of huge double doors around the arena slide open. From behind the flying dust, a huge Titan comes thumping out. You are in for a real fight here!
The Titan is huge and highly durable. Keeping the central pillar between you and it to avoid the deadly rocks it hurls, circle strafe and fire Eightballs in clusters at it whenever it appears from behind the pillar. Expect to use almost all of your Eightballs if you're a good shot, and more if you're a bad shot, before the Titan falls. Failing the Eightball Gun, use the ASMD in primary fire, then the Stinger in primary fire, then the Automag. However, that shouldn't be necessary.
When the Titan is dead, the back wall of the alcove behind the middle doors will collapse revealing a hole to a corridor beyond. Before going through, collect the contents of the three alcoves: two Nali Healing Fruit, a Shield Belt and two cans of 12 Eightballs.
Go through the new hole and around a short corridor into the area beyond, which is a small room beneath the door opening mechanism above. Shoot open barrels here to collect two Health Packs, then press a switch on the wall between two torches to open a door at the bottom of a short flight of stairs. One short stretch of corridor later, you've exited the level.

Note: There's a Super Health Pack in a recess on top of the main arena's central pillar. I couldn't figure out how to get it at first, but there are two ways. TheBypasser points out that it can be reached by a well-timed lift jump off the rising gantry (jumping whilst the gantry is in motion), making sure that you don't jump too late as the gantry begins to decelerate towards the top. Alternatively, Inuit Chief sent in a suggestion which works, but I think it's too hazardous to be worth it. As you enter the arena, ride the gantry to the top. When the Titan comes out, stay on the gantry support, pressing yourself against the pillar. When the Titan hits the ground, you will fly up and with some good trajectory control you can land on the pack. Nice, but very dangerous. Thanks for the suggestion!