Note: I am a mesmer that reached 20 yesterday and wont go to 20 until Friday.
At 10-18 you start to see a chance of getting a (Uninfused) ring from the Daily chests (your first even numbered fractal of the day). From what I can tell it is rather frequent, but I am 0/3 of getting one.
As for the Exotic Back, It was rather recently found out that when put in the mystic forge with a Gift of Ascencion, a Vial and 24 skill points worth of Philosopher stones (defensive infusion slot) or Crystals (offensive infusion slot) you get an ascended version of it.
So it is an ascended back that doesnt take 30-80 gold to make it.
As for Globs, They are used to make Infusions with more than just the 5 agony resistance.
For relics, I actually bought the Exotic box saving me ~12 gold on making/buying a bag. But if I'd known at the time about the Prototype ascended version, I would have saved up for it.
As for Agony in 11-19, I've done it all with 0 resistance and I have only died a few times but only when I deserved to die (see when I didnt avoid boss mechanics).
In those levels, agony only appears during boss encounters. And bosses only have agony for "Standing in the fire" mechanics and for the exception of Jade Maw, Every bit of agony can be avoided when played correctly. And even if you dont avoid it, it is generally healable as long as you dont get hurt for a bit after.
-In the Cliffside fractal, The First and Last (since they are the same) boss drops wells, same as in 1-9, but in 10-19 their initial hit give agony. You can heal through this as long as you dont get hit by the initial attack of multiple wells.
-In the Asura fractal, The asura's Ball projectile (yes they can be reflected) give agony, but as long as you are far away you can dodge them. You can heal through this easily.
-In the Swamp fractal, both bosses have a agony inflicting attack. Mossman with his reflectable daggers, Bloomhunger with a "Poison" AoE that can be avoided. Both you should be easily able to heal through.
-In the Dredge Fractal, The Powersuit gives a shockwave that gives agony but can be avoided by range. The Ice Elemental's AoEs give agony but you can avoid the red circle.
-In the Ice Fractal, His many AoE's when he teleports away give agony, but it is easily avoided.
-In the Grawl Fractal, His debuff that he puts on people (the one that burns you and others near you) give agony on the initial hit, but can be reflected.
-In the Ascalon Fractal, At 50% he does a Burst on him that deals a lot of damage and gives agony. This is probably the only attack that if you get hit you probably wont be able to heal through. But it can be avoided by range.
-In the Underwater Fractal, I'm not too sure when he gives agony, but I think it is when he "Eats" a player. It is very healable and avoided by range.
-In the Jade Fractal, This is the only one that has unavoidable agony. When the Jade Tentacles mass spawn (when you kill the 2nd initial tentacle, and when you destroy the last Jade Colossus) Everyone gets a rather long Agony (I think 9-10 ticks). Me a glass cannon mesmer can heal once and come out without going down (but with rather low health like ~1k/18k). But you should be in a position where you arent in any danger when it happens anyways.
Edited by Eyebrows89, 22 November 2012 - 06:14 PM.