maybe will help in some parts,
1. The Beast Within.
Get this quest from the General in Thunder River BEFORE you enter the cellar, to get the fragments. To get quest so that you can enter, first you'll need to find the entrance to Xibaluku, which in turn will take you ultimately tanco Rhea and in turn to cellar for the seals.
2. Entrance is one way, so make sure you have plenty of potions for a 2-3 hour trip if you're looking to clear whole zone.
3. Climb all the way down the vines and drop through hole onto the rocks beneath (don't die its a long drop from vines or from the hole)
4. Undead:
All undead apart from minions when near dead have a chance to run off to a nearby bone pile to heal up
Shadowcasters - range casters doing medium amount of damage, also when aggro can activate nearby zealot minions.
Lookouts - Archers, very hard hitting range mobs - think of the archers from upstairs in aztel fortress
Battlemasters - medium damage melee, capable of stun attack
Zealots (minions) hard hitting melee, but low hps, kill them quick before getting swarmed.
Bosses "upstairs":
Warlord Regalis - hard hitting boss who summons 4 minions at a time, repeatedly until dead up on the ledge overlooking his room.
Suggest you fight boss up on ledge where minions appear to assist with fighting as a group so all benefit from heals / AoE damage on minions.
Gaoler + dog
Quite hard hitting bosses, gaoler will often summon dog away from whoever its attacking to assist him.
Focus on Goaler first, once dead focus on dog, who has chance when near dead to run off and eat a corpse to heal to full - this is a dps fest, ie kill it before it heals
Additionally, there is a chance a random person will be sent to a cell for their crimes, there fight 1 or 2 minions before being released.
Once dead click on bars at rear of room to open them revealing a chest - this is not mob loot, so it wont be displayed to rest of group - be honest with contents!
Acheronian Reaper (rare boss - method of activating, I think its timed from the moment you enter dungeon, also no one in party must die prior to spawning him?)
Located in cave next door to the wounded scount.
Has shield you have to dps your way through before being able to damage the Reaper. The closer he is to dead, the harder he hits, towards end it can get quite scary!
Stairs / Golem / Bats ? Green artifact (benediction of acheron - touch to remove tombstones)
Golem is indestructible and does an AoE knockback / damage attack.
Kite golem allowing others to go down stairs ONE AT A TIME.
Avoid left hand edge and areas on ground with holes, since there are spike traps.
Kill any minions on ramp.
Bats are attracted to movement down the stairs, when they appear they give a bat debuff, draining approx 150 hps per sec, for 10 seconds. If you move more whilst bats are swarming this debuff will stack up to 600 hps per sec for 10 secs. So the moment they appear STOP. Wait for debuff to finish and heal to full before moving on.
At bottom wait on rocks towards right hand side away from the minions walking around.
Last person down will likely have golem chasing them so may need to sprint down - jump / avoid pit spikes. If dead get a res at the bottom. If message received that you can't due to someone fighting then back all the way into corner with rocks, with everyone else, then walk forwards and try and res again.
ONLY fight the minions at the bottom when everyone is down, since the minions will keep respawning and will typically appear on stairs down - not a place to have a fight!
Bosses downstairs:
Balkan - do this in one attempt since otherwise wipe likely and have to get you all past traps again. Kill it and golem and bats disappear for remainder of instance.
Boss does nasty mana discharge attack AoE damage short range - other than that, a normal dps fight. Spellcasters at rear watch for minions that respawn behind at start of fight - they stop coming as fight commences.
Champion / Ravager / Vindicator / ? of Acheron
Next boss differs from instance to instance in terms of its class.
All versions have minions spawn in the back of his room, suggest you fight outside of room. Minions aren't too bad, focus on boss with dps, unless you're a fragile spell caster in which case take out any minion on yourself.
Ranger version: total wuss!
Champion: One of the nastier versions who has ability heal up after a while.
Vindicator: spellcaster, but not that bad, unless minion waves build up.
Any of these bosses have chance to drop the Tainted Alkehest recipe (confirmed) + pet (not confirmed)
Martyr
Very hard hitting caster boss, summons other epics (not minions) who are also casters, with each spell having chance of knockback.
Kite boss well outside of room to either glitch the boss when he resets, or to provide time for others to work out order for orb pressing in his room.
The orb order differs from instance to instance, object is the click on orbs to make a path across gap to final orb which reduces boss to 5% health.
When next pad appears you have about 1-2 seconds to move to next one before the one beneath you disappears (although you wont drop down until you try and move)
Tia Shar
Spellcaster boss who doesn't do much damage herself
Summons Acheronian Avengers, who are slow moving, insta hit killing machines when they touch (which in the process destroys themselves)
Tia Shar summons them next to her with an ability above her health bar called "Arise Acheron", at which point back off from her, whoever is being chased by the avenger shouuld kite it away.
You can destroy the avengers by guilding them into the small rings of fire that randomly appear on the ground.
Tia Shar's glowing ball next to her can drop at end of fight as an item that can be picked up to generate a new quest "Handmaiden of Acheron" which can be turned into Rhea for a silver reward.
The Red One
Clear all adjacent rooms and corridors before fighting boss as he moves around a lot and has a fear effect
Hits quite hard, suggest you have all group members within fear range since whilst feared you tend not to get hit much, which will keep fragile chars alive
Rare boss - name uncertain
Location: Pool of water after Red one
Trigger for spawning him - unknown
Avoid line of sight from his spirit lock - critical, as it does huge damage ending in an insta-kill
Jal Kor Bloodbane
This boss hits like a TRUCK with melee damage, so you MUST have a guardian tanking.
Avoid fighting him in the pool where the reflected light bounces around since this does around 7k damage per hit.
Boss summons a guardian spirit which is indestructible as well as slow moving and follows after Jal Kor. If near Jal Kor it will confer 100% immunity to boss. So you must keep boss on the move at all times.
Currently it is possible to fight boss outside of whole area by all being behind where doors close off when boss is aggro and sending in a pet to fight boss - then running away before pet hits.
Alternatively, fight boss on ramp on other side of pool. This method will involve a wipe of party, apart from healer who you get to climb the vine on other side to safety. The others should then die at base of vine. Boss will then lose interest in the person up the vine and reset. Healer can then come down, res everyone away from boss. With everyone alive you can go up ramp and fight boss there (more room to fight / kite, further away from ghost - hence takes longer to catch up)
Do not enter doorway on ramp, its a one way doorway out of dungeon to below prison colony.
Mini Yakhmar boss (unconfirmed)
Somewhere after Jal Kor Bloodbane - possibly on the ramp mentioned above
Purpose of Sacrifical altar near Tia Shar - unknown.
Animal carcasses and Acheronian Metalwork (just before Jal Kor Bloodbane encounters), can be harvested for resources - chance of getting rare resources.