Sire Denathrius
Sire Denathrius is a three phase encounter which has the raid fighting the boss in two different encounter spaces! During Phase One, the raid has to manage their Burden of Sin stacks and bring them low enough to survive the March of the Penitent intermission. In Phase Two, you fight the boss and his sword, Remornia, whilst dealing with adds in hard-to-reach locations! Phase Three is a race to the finish, as you need to defeat the boss before he coats the room in deadly Desolation pools.
Sire Denathrius is the final boss of Castle Nathria, third in the Royal Quarters Wing, encountered after defeating the Stone Legion Generals.
Sire Denathrius Quick Tips in Castle Nathria (Normal)
Phase One: 100% - 70% Health
The raid is split into two even teams. These teams take turns at standing in the Cleansing Pain cast.
Move away from others when marked with Feeding Time.
Move from the Ravage cone and don't stand in the Desolation pool it leaves behind.
Kill the Echo of Sin adds as soon as possible.
Make sure you have less than 3 stacks of Burden of Sin when the intermission begins.
Run to the middle of the room to survive the March of the Penitent intermission.
Phase Two: 70% - 40% Health
Kill the Crimson Cabalist adds as a high priority.
Position the Wracking Pain to hit the adds and not the raid.
Taunt off of one another after each Wracking Pain cast.
Position the Remornia add near the boss to allow DPS to cleave damage onto it.
Place the boss near the mirror for the Hand of Destruction. Run through the mirror when the ability begins!
Move away from others when marked for Impale. Other players need to dodge the path it takes as the sword charges around.
Dodge the large Massacre sword lines!
Phase Three: 40% - 0% Health
Kill any remaining Crimson Cabalist adds as soon as possible.
Stand around the middle of the encounter space to avoid the Indignation goo.
Position the boss towards the edges so that players are knocked into the middle when Shattering Pain is cast.
Move away from others when afflicted with Fatal Finesse.
Dodge the Massacre swords and kill the boss before Ravage is cast three times.
Sire Denathrius Heroic
Phase One: 100% - 70% Health
The raid is split into two even teams. These teams take turns at standing in the Cleansing Pain cast.
On Heroic, the same group will take the first two hits, back to the wall, the next three hits will be the second group, before the first group takes the final hit.
Feeding Time is replaced with Night Hunter - two raiders will be targetted. If they can immune, they move away from the group, if not they move to outside edge of the outside wall, allowing other raiders to stand along the line to help soak. No-one other than target should be in the circle around the target.
Move from the Ravage cone and don't stand in the Desolation pool it leaves behind.
Kill the Echo of Sin adds as soon as possible.
Make sure you have less than 3 stacks of Burden of Sin when the intermission begins, unless you're confident you can "cheese" it.
Run to the middle of the room to survive the March of the Penitent intermission.
First position prior to first Ravage - circles show positions of those targetted by Night Hunter, and the beam that others need to stand along (don't stand in both!). X Shows position of first soak group, Skull position of remainder.
Following Ravage, the groups will have moved to a similar position further around the room, with X and Skull positions swapped. Following 2nd Ravage, again groups move to similar position further round - X taking first wall side position, then Skull.
Phase Two: 70% - 40% Health
Kill the Crimson Cabalist adds as a high priority.
When a Crimson Cabalist add dies, it will spew out a volley of anima towards random players locations - avoid!
Position the Wracking Pain to hit the adds and not the raid (tanks).
Tanks taunt off of one another after each Wracking Pain cast.
Position the Remornia add near the boss to allow DPS to cleave damage onto it.
Place the boss near the mirror for the Hand of Destruction. Run through the mirror when the ability begins!
Move away from others when marked for Impale. Other players need to dodge the path it takes as the sword charges around. Note this leaves red puddles on the floor - avoid! Impale targets should line up along left edge of platform, as if facing mirror, and try to ensure their correct order (arrow will show if you're 1, 2 or 3).
Dodge the large Massacre sword lines! (These also leave red puddles on the floor on heroic if you're hit).
Phase Three: 40% - 0% Health
Kill any remaining Crimson Cabalist adds as soon as possible.
Stand around the middle of the encounter space to avoid the Indignation goo.
Position the boss towards the edges so that players are knocked into the middle when Shattering Pain is cast.
Move away from others when afflicted with Fatal Finesse (big red circle) - on heroic stay close to others targeted. The remaining small circle/ball require to be soaked within 10 seconds or it will explode causing raid wide damage.
Dodge the Massacre swords and kill the boss before Ravage is cast three times.
Phase 3 - showing Fatal Finesse positioning. Most times will only be a set of three, but occasionally two sets. Position first set at range, second set at melee.
A full guide can be found on Wowhead: https://www.wowhead.com/guides/sire-denathrius-castle-nathria-raid-strategy-guide