The buff received upon entering, Fount of Power, if one does not have ~125k Potency and ~20+ million hit points, cancel buff, and recast from button on hotbar.
You may want to pick up the Solo Mission quests for the two zones first.
Return to ( 296, 71, -323 ) Copy/waypoint 296, 71, -323 and take the other fork.
Along the path there will be green clouds. Entering them will spawn a giant latcher and two pusling leakers
Run back down the path to avoid the giant latcher and kill the two pusling leakers. The latcher will despawn.
If the latcher latches on, it will toss you in the air. Be sure to direct your fall so you do NOT land in the green slime. If you land in the green puddles, you die.
Continue along the path.
Kill The Flesh Eater near ( 227, 392, 10 ) Copy/waypoint 227, 392, 10.
Be sure you used Hirudin Extract from earlier or the named will regenerate hitpoints quickly.
Do not step into the water, it ticks for ~1m damage.
During the fight a putrid pile of flesh will spawn. If it gets to the named, the name heals slightly.
Go back down the path and to ( 68, 75, -308 ) Copy/waypoint 68, 75, -308 and take the right fork.
Kill High Dragoon V'Aliar wandering near ( 35, 94, -228 ) Copy/waypoint 35, 94, -0228 and loot a Damaged Rune of Symbiosis and use it.
Kill his adds first.
Periodically through the fight he will root himself and start casting Magnetic Charge. Joust out of the black lighting cloud.
DO NOT attempt this fight without Singular Focus, if you do not have this it can be purchased from your class trainer Furthermore, if you have the current "Best in Slot" weapons, they all have AoE effects that are NOT turned off by Singular Focus. Never ever get out of the zone to go on Scintillating Spires Island and grab a set of "free" weapons, you will loose key items and can't get them back (except for Springview Healer Mask). Even worse, the reset timer for that zone is 1h30 at least. You can find a safe spot where you can't aggro the bats even with "small" AoE spells / weapons.
The water will dispel your buffs, keep an eye on them
The named will one shot you, if you pull one of the bats together with him.
Capture at least 4-6 (the more the merrier) of the yellow balls by carefully approaching them and clicking. Watch your health while in the water and avoid running into them since they dispell.
Use the resulting Bileburn Spores on some bats. Those bats will then ignore you if you approach, so you can pull Rallius without bats.
The bats don't "totally" ignore you. They will get aggro when you get really close to them. The effect also times out very quickly. If you're sure of your singular focus, you can nullify 4 bats and then pull him from range. The island is a good place to pull from.