I came to a terrible realization. I came to this realization when I failed the Snowden Drifts DRM CM over and over again... except for the time I played a DPS in which we won. That realization is this: nobody actually knows how to defeat Ryland. It's weird, I know, but time and again I see all of my teammates scattered to the winds and defeated. Rejoice, however, for I, the magnificently sexy and humble Blood Red Arachnid, am here to tell you how to fight Ryland without getting laid out in 5 seconds. The tl;dr is you circle around him while whacking him. The long version:
Now, the Snowden Drifts DRM is simple enough. The most infuriating part is that the escort didn't take his Ritalin, so he lollygags about every time an icebrood shows up. Keep swiftness or superspeed applied to the escort and run backwards a bit if he decides to take in the scenery. Now, for the boss:
Ryland has a fairly set pattern. Once you know this pattern, the only hard part of this fight is all of the random stalagmites that erupt from the ground. At the start of the fight and each time he phases, he's going to do this:
Channeled Attack where he rains Ice Spike down.
Now, although it is very tempting, DO NOT USE THE EMP SKILL ON RYLAND. It stops the channel attack without stunning him, and gives him a ton of boons. Now, you can CC him during this attack, but it is actually pretty easy to avoid. You can let him stand there throwing ice down because it is easy to DPS him during. 1 He will occasionally start the channel attack again. However, when he is not channeling this attack, he follows this pattern:
Big Horizontal Swing (CC)
Cone Damaging attack
Big Horizontal Swing (CC)
Swing 1 and Swing 2 don't do much damage. The Big Horizontal Swing is the telegraphed launch skill that sets you up for his power attacks. The cone attack does massive damage and will probably kill you outright. The Spin attack does a lot of damage, and will usually knock you into a forming stalagmite which will kill you.
So, how do you avoid getting clobbered by his clearly-compensating-for-something sword? Ryland has a pretty big weakness in this rotation: He get gets tunnel vision after swing 2. See, swing 1 and swing 2 will track you. However, after swing 2, Ryland is so focused on topping the DPS meter that he quits looking at what he's doing, and instead looks at his skill bar. He will proceed to unleash his next two attacks without turning to face the player. This is where you can damage him relatively safely. Just move to Ryland's back after Swing 2, and then you'll avoid the Big Horizontal Swing and the Cone Attack. However, you'll still want to dodge the Spin Attack, which has a large, telegraphed AoE.
Once you're used to his pattern, the only hard part of fighting Ryland is the random AoEs that encircle him. So, when you circle Ryland while attacking him, you'll want to pay attention to not stepping in any of circles around him. Ryland will phase at 70% and 35%, in which you have to run to 3 corners of the room and kill an elite mob that spawns. Ryland will return to the fight after these enemies are killed, and he'll begin the cycle all over again.
The time limit is tight in this mission, so you'll want to bring as much DPS as you can. The obstacle that most groups face is staying together for boons and buffs, since the natural tendency when faced with Ryland's big sword is to cry out for mother while running about in panic and despair. It should be noted that the Spin Attack can be blocked by aegis, so having a Healbrand or Guardian that is on-point with Retreat can really up the damage time when fighting him. Occasionally Ryland will get a bunch of boons, so it helps to have some form of removal/corruption in the team. Otherwise, I make no further profession recommendations.
Remember: you lose the most DPS when you go down, so prioritize staying alive during this fight. It is better to avoid the attacks and not do damage than it is to eat the attacks while trying to power through them.
"Self awareness is knowing when you're sitting at the throne of ignorance." --Leo G.