I'll continue adding onto this over the next few days, but let's get started!
Gruul
A fairly simple Patchwerk-esque fight. Gruul frequently cleaves the target tank, splitting damage to other raiders inside thus requiring stacking groups. He also utilizes the old Petrify effect from his original incarnation, requiring afflicted players to move out of the raid before Shattering.
Inferno Slice is used approximately every 17-18 seconds on the current tank. It has a 2-second cast time, after which it inflicts massive damage to all players in front of Gruul. Also applies a 30-second stacking fire DoT and debuff that increases damage taken from Inferno Slice by 20%.
@Tanks: Gruul can be taunted mid-cast of Inferno Slice, and he will use the ability on the new tank at the end of the cast. Moreover, because the cast frequency is over 15 seconds, taunt DRs will not apply if no other taunt periods are required.
Overwhelming Blows is also a cone attack used on the current tank, dealing damage to those in 10 yard and applying a stacking debuff for future Blows. Ideally this ability combined with Inferno Slice debuff will dictate the tank swap requirement.
The raid will be positioned into 3 positions forming a triangle in melee range:
Code:
TANK
BOSS
CAMP A CAMP B
@Tanks should utilize a rapid pre-/post-Inferno Slice taunt tactic, to ensure more reliable avoidance of Overwhelming Blows for non-tanks and to simplify management of Inferno Slice damage distribution:
1. Tank A starts on the boss in the TANK position, while Tank B is designated as the Slicer Tank and starts in CAMP B.
2. When Inferno Slice is cast, Tank B (the Slicer Tank) has the 2-second cast time to taunt the boss, forcing Inferno Slice to cleave himself and CAMP B raiders.
3. Immediately following the Inferno Slice cast, Tank A taunts Gruul back to himself.
4. The fight continues as normal for another ~15 seconds in which time the Slicer Tank has moved over to the other side in CAMP A.
5. After the 15 seconds pass and Inferno Slice #2 is cast, the Slicer Tank taunts once again during the cast, with Tank A taunting back right after.
6. This process repeats perhaps 1-2 more times, until just before Tank B has a dangerous stack count of the Slice DoT/debuff.
7. Once a tank transition is required, the same pattern begins on the next Slice cast, where Tank B as the Slicer Tank taunts the boss mid-cast. However, this time Tank A does not taunt back.
8. Instead, immediately after the Slice hits the current CAMP position, Tank B rotates back to the front TANK position and holds the boss from that point on, switching roles with Tank A (who has now become the Slicer Tank). The entire process repeats back and forth, every 3-4 Slice casts as necessary.
Overhead Smash is used frequently and targets a random raid member and smashes the ground in their direction. Simply sidestep to the left (clockwise) to avoid the attack, then move back into the original position.
Petrifying Slam is cast frequently and will target a handful of random raid members, Petrifying them over a short period before Shattering anyone in 8 yards. This ability simply requires afflicted players to spread out in the open space around the room away from others, using personal CDs if necessary to soak the damage.
Rampage is used infrequently, where Gruul will use multiple Smashes in rapid succession. As before, these should be avoided, but always being sure to move in the same direction (left/clockwise by default) as the rest of the raid group to avoid them.
Oregorger
On a personal note, this looks like a unique and fun fight. Oregorger has essentially two alternating phases, going from standard tanking method in the first to rolling around the entire room in a crazy frenzy looking for ore to gobble up in Phase 2.
Standard Phase: 100 to 0 Mana
Oregorger will be tanked with melee behind the boss in two equal groups (standard triangle formation with tanks), tanks in front, and ranged/healers 25+ yards out behind the tanks:
Code:
MELEE A MELEE B
BOSS
CURRENT TANK
OFF TANK
RANGED
Oregorger uses a handful of abilities in this phase, all of which cost him some of his mana. When he reaches zero mana he transitions into the Roll Phase. Since this Standard Phase is easily the simplest phase in the fight and allows for the most DPS time, it is in our best interest to reduce the amount of mana he spends, thereby prolonging the phase.
Every ~20 seconds Oregorger gains a 3-stack of Blackrock Spines, at which point he can (and often will) immediately cast Blackrock Barrage, a 2-second interruptable spell that deals moderate damage to the raid and reduces his stack of Blackrock Spines by 1 for each cast. Since he gains a 3-stack every 20 seconds, but once that stack is gained he can chain cast Barrages back-to-back, we need at least (3) assigned interrupters to stop each Barrage cast from going off. Since each successful cast costs him 5 mana, allowing any cast to succeed will shorten the length of the phase significantly. We'll likely want to have (3) pairs of two players, just in case one person misses his or her cast in the rotation.
Acid Torrent is the most interesting ability of the phase and is used about every 12 seconds. While this ability also costs 5 mana for Oregorger, it cannot be interrupted. Instead, Acid Torrent targets a random ranged player and shoots a bolt toward them, hitting the first player it contacts for very heavy Poison damage. The bolt "splashes" or spreads off the initial target and hits all players behind the initial target for reduced Poison damage, where the damage reduction is based on the mitigation and possibly absorption of the initial target. The initial target is also afflicted by a 20-second debuff that increases future Acid Torrent damage and thus is the primary @Tank swap mechanic.
When the Current Tank is in front and Acid Torrent is being cast, a personal or outside CD (including absorb shields perhaps?) should be used to dramatically reduce the initial hit damage, and thus reduce the subsequent hit to the ranged behind. Afterward, the Off Tank moves in and taunts and the tanks swap positions/roles for the following Acid Torrent, and this pattern repeats throughout the phase.
Explosive Shard is another mechanic used less frequently but is also uninterruptable. When used, a random @Melee has a Shard thrown at their location, dealing a small amount of damage and knocking players back in a short radius. After 3 seconds, the Shard will explode, dealing heavy damage to anyone in range.
Therefore, this is the reason we'll form two equal melee groups, positioned in the opposite, back sides of the boss. When the MELEE A group is selected and knocked away, they then move into the other MELEE B camp temporarily until the explosion goes off, after which they move back to their original position in preparation for the next Shard cast. This should allow us to avoid all explosion damage and only have half the team afflicted by the initial hit/knockback.
Retched Blackrock is the final ability in the Standard Phase and simply throws a pool under the feet of a random ranged raid member. Since ranged will generally be stacked up due to Acid Torrent positioning requirements, the group will simply move out of a pool to the next safe location for each cast.
Roll Phase: 0 to 100 Mana
Once Oregorger eventually reaches zero mana he'll be like, "Zomg, I'm like super totally hungray and stuff!" and begin rapidly rolling around the room in short spurts, attempting to feed off the ore stashed away in the chests in the area.
Any player standing in Oregorger's path will take massive damage and be stunned, which is bad mkay? The top-down view of his room shows five "islands" with everything in the room being equidistant from opposing matching objects and made up of exact square bricks. When Oregorger chooses a path to take, he can only ever start in the a direction exactly left or exactly right, and will follow a standard path from that randomly chosen direction until he hits an inner wall, at which point he pauses and repeats the left/right choice.
Below you can see the rough diagram of his room. Blue bricks represent "stopping walls" or areas he cannot move through, red circles are his potential stopping points, and white lines are his potential paths from those stopping points:
Since Oregorger is always facing the inner wall from each stopping point, it's clear to see where his next path will take him whether he chooses to go right or left.
Note: I cannot confirm from footage, but it appears there may be a completely safe location from his charging around in the very northeast corner of the room.
Meanwhile, while Oregorger is charging around, the raid must quickly destroy the attackable Ore Crates around the room (these may spawn in the same pattern/location every time?), allowing Oregorger to pickup the Ore and gain back some mana when he passes through. Once we locate where the destructible crates are located, it'll likely be worth assigning players to various crates so we can quickly destroy them at the start of the phase.
That's it. Standard and Roll phases alternate until he dies. It's also worth noting that oregorger may have a Frenzy mechanic of sorts where he chain casts Earthshaking Collision when reaching low health percent (10%?), but the available footage shows it is bugged at best and is not increasing in damage over time.