Before I begin, let me say it another way - this is not for everyone. Farming this area is hard to do effectively, and you are unlikely to do it efficiently your first try. If you like big challanges and rewards though, this is the spot for you! (I, of course, cannot guarantee your drop quality)
First up, is how to get the Titans (yes you read that right - Titans!) you will be killing for this run to spawn. You must have the Defend Denravi quest (repeatable). In order to get this quest, you must A) complete the mission Hell's Precipice (hey some incentive to do it!) B) complete the quest Defend Droknar's Forge, which you can recieve (after you have completed Hell's Precipice) by kneeling at the shrine to Glint at Droknar's Forge (its nearish the Xunlai Storage Agents).
All quests Glint gives are repeatable, so you can farm them for XP if you really want to, but in all honesty Troll farming with a cheap scroll is faster XP. While attempting the Defend Droknars Forge (DDF) I recommend you bring heavy hex removal (shatter hex = godly) and a -energy switch, because the Titans there (which I dont suggest you try to farm =) ) will be hexing you with Malaise and Wither. After you have the Defend Denravi (DD) quest (also recieved from the Vision of Glint) you can head on over to Denravi, and get ready to farm. =)
Next is the build. I use an I-Monk for this, utilizing Mantra of Resolve from my Mesmer secondary to avoid interuptions by the Water Born Titans. Mo/Me and Me/Mo can use the same skills and (roughly the same) attribute points, but Mo/Me is better suited. It is also *possible* with a Necro using Spiteful Spirit and also as a Warrior primary with armor buffing skills, but not recommended due to problems with interupts and healing.
Here are the two weapon groups I use. Sometimes, I switch the -HP offhand out for a sheer energy booster, depending on my DP and need for energy.
The reason Im using a Brute Sword is because I stole it off of my Warrior. I sold my HOD sword - a decision Im regretting. If you have one for sale, you know how to find me ingame =)
Perfect equipment is not in any way required, but is of course prefered. A set of normal armor (no sup runes), a set of I-Monk armor, and several Scalp Designs (head armor) with varying strengths of runes is highly suggested. This allows you to switch armor out to achieve the ideal mix between HP and attribute points, at any DP (Death Penalty). I personally have 2 pieces of armor for my hands, legs, and feet, with 4 pieces on my chest (one for each type of Vigor rune - none through superior), 6 on my head, and a 4 different Swords/Axes of Fortitude. (I use my I-Monk often in very sticky situations, so it is essential I be able to switch equipment quickly as I loose DP and my HP rises)
Having to switch armors in battle is (all but) essential for this run. Get used to it, and be prepared =) If you do not have a purple/gold -20 focus, one can either be bought for around ~5k, or obtained by completing the Poor Tenant quest in presearing. (near Devona & the guy with the bee problem) Purple/Gold -20 focuses are best as they provide the most energy, but are far from neccessary.
Zealots Fire and Holy Strike are personal favorites for this run, however I have only rarely done this run after the AOE nerf and I am sure my build is still flawed so feel free to experiment. I consider the rest of the skills neccessary, and you may like to bring Arcane Echo or Blessed Aura to buff Shield of Judgement. Also, Symbol Of Wrath is a perfect skill if you know how to manipulate mob's AI to keep them from fleeing from AOE's. If not, its probably a poor skill to have - but one I enjoy profusely, as its 'spike' damage helps me kill Wild Growths without bothering to interupt their Troll Ungent.
When you first walk into Tangle Root (the area outside of Denravi) Evennia will be standing with a small escort. Ignore her, and do *not* talk to her. Doing so changes the spawns, and causes the quest to progress as scripted - which is largely about you defending her, something an I-Monk is unable to do effectively. Switch your armors out and use a +1 Healing Scalp in order to reach 13 Healing then cast Mending. (*highly* suggested, not required. Wild Growths have Poison, which is -4 HP degen, the same as the bonus provided by Mending at 13 Healing) Cast Balthazar's Spirit, then switch your armor back to reach 55 HP.
Follow the path, and soon ~3 Titans will pop out of the ground and attack you. Do not die to them or retreat, as they will run towards Evennia. And while her guards can probably protect her, its alot easier if you just handle them. Use Mantra of Resolve only if you are facing a Water Born Titan, elsewise save your energy. If youve decided to use Zealot's Fire, try spacing your casts of targeted spells (Protective Spirit, Healing Breeze, and Shield of Judgement included) by a couple of seconds, to prevent the Titans from scattering. If you have few Titans left, use Holy Strike on the ones which have the most HP, and try to get them to all die at roughly the same time, so you do not get stuck with only one Titan left, who is at half HP, while your Protective Spirit is about to run out, with no energy to recast =)
While you are fighting them, a swarm of friendly critters (whom, if you dont have the DD quest, are significantly less friendly!) will likely run past you and Evennia, to take refuge inside Denravi! Note the direction they come from (west) as this is where you are going. Proceed and run to where the minimap indicates in the bottom picture below, in order to get a large number of Titans to pop up. Here is a before and after picture of the farmed area:
Wild Growths have Troll Ungent and a fairly high Wilderness Survival, so unless your build is set up for direct damage it is unlikely you will be able to kill them. I personally do not bother as slaughtering the rest of the Titans quicker is more profitable.
Wild Growths use Apply Poison and Spike Trap. While attempting to aggro all the Titans make sure you precast Healing Breeze so you do not get KD'ed without it on. Intentionally trigger Spike Traps when you are prepared for them to keep from getting surprised later. Killing a Wild Growth results in an Earth, Air, and Water Born Titan to spawn.
Keep Mantra of Resolve up constantly until all the Water Born Titans die. If you only cast when neccessitated, you will actually GAIN energy from Maelstroms, even with Mantra of Resolve. However, the result is a massive spike of energy loss, which combined with the -50 icons unreliable conditional energy boost, can put you in a bad place, quick. Make sure you have enough energy to withstand interuptions. If you use Arcane Echo you may want to increase your Inspiration.
If you have many Titans who are not near death, use Holy Strike on the mobs which are going down the fastest (note, this is important) so that you can anticipate the change in DP and change your armor/weapons/foci as needed. Of course, if they are attacking through Shield of Judgement (and not all will) try to coordinate Holy Strike with their knockdown. Holy Strike is not a spell, and will not be effected by Maelstrom.
Unless you are prepared, avoid Rotting Titans like the plague. They have heavy degen and Rend Enchantments. Any questions?
Do not be afraid to fight the Titans with heavy DP. This will allow you to, with practice and quick reflexes, accurately control your HP. I personally die a few times intentionally before I begin farming for just this reason. I can reach 17-19 HP (ideal for an I-Monk) at most DP's more then ~15%.
If you are able to kill the Titans, you will be rewarded with any number of items. Their favorite drops are Molten Claws (redeemable for XP scrolls at a Collector on Perdition Rock) and Titan Armors. In the run which I screenshotted for this guide, I found 1 Rare, 3 Purple, and 1 Blue Titan Armors - including 2 Major Vigors. This is an average drop for the run. Titans also drop "Magmas Arms" which is a rare name for a common hammer skin, as well as Magmas Shields, which is a common name for a rare (and valuable) shield skin =D
Beware, I cannot guarantee your drops, but I can say that I have gotten MULTIPLE Superior Vigors and Superior Absorption runes here (they seem to drop lots of Warrior runes for me...) and also several other very high quality Gold weapons. Being Elementalists, they tend to drop elementalist items, but it is not all that uncommon to find gold FDS and other valuable items here.
It should be noted that it seems that Anti-Farm has a disproportionatly heavy influence on rune farming spots, or any place where you are making more a gamble with your time. This is to say, you could get 10 Gold armors, that all ID to Majors, or 1 Gold that turns out to be a Superior Vigor. The first is more likely to happen if you are suffering the effects of Anti-Farm. This is what I have observed in my tests, at least. I use strict controls, too, so it is unlikely my results are contaminated. In order to defeat Anti-Farm I switch where I farm after every run, and often change secondaries/characters as well. I rush a mission or two every rotation through all the spots I farm, and I very rarely suffer from Anti-Farm. (anyone caught referring to the "Anti-Farm Code" will be shot on sight. questions about "Anti-Farm" are acceptable, as are any synonyms that do not make my, a coder's, blood boil.)
Next up: How to farm (those damn) Mursaat!
hahaha. 
That's a good idea, someone should implement that 
Otherwise we could have finished the mission. GJ on the idea.
