Nexus-Prince Shaffar Heroic mode

Heroic mode

This fight is extremely difficult in Heroic mode compared with the rest of the instance. The beacons turn into apprentices much faster and spawn with 7000 hits (you may have trouble in killing all initial beacons before they spawn), and new beacons are spawned at an increased rate. The fight is very difficult with certain group makeups, as it is extremely difficult to deal sustained melee DPS to Shaffar because of his near-constant usage of both Frost Nova and Blink.

It is strongly recommended to not attempt to ignore the adds (an effective strategy in some other similar fights), as they pile up very quickly and their damage output will overwhelm almost any group well before Shaffar can be taken down. Because they appear in semi-random locations around the room, it is difficult to chain-fear them (although a Warlock can manage this to some extent, and Curse of Tongues will help to mitigate the adds' damage while they are not feared.) It is extremely difficult for any tank to hold enough aggro on all the adds, so your healer(s) will eventually be focus-fired down by the uncontrolled ones.

The main thrust of the fight is sustaining relatively high DPS on Shaffar while killing and/or controlling the adds well enough that your healers are not overwhelmed. Shaffar uses multiple types of magic, so it is difficult to mitigate his attacks substantially by stacking resistance; healer mana usage generally becomes the limiting factor. A high-HP tank is preferable to one with a lot of avoidance/armor, as Shaffar deals comparatively little melee damage.

Melee DPS is at a substantial disadvantage when fighting Shaffar. He uses his Frost Nova and Blink abilities very frequently to move out of melee range, and trying to track his movements can be extremely disorienting. It is strongly recommended to use melee DPS on the adds and ranged DPS on Shaffar if at all possible. These abilities also make Shadowfiend usage much more dicey, making the fight even tougher on a Priest healer.

Alternative Strategy 1

The boss can be done with a slightly under-geared but properly-coordinated team by employing a suicide bomber strategy with two mages in group. Essentially the tank engages and holds the boss while the mages rush in with fast Arcane Explosion burst damaging the ads, at a point where the ads are low, the mages would switch to the boss, now with enough threat on the boss, and pop all cooldowns and go all out DPS, switching back to AE-ing the ads possibly when they start getting out of hand again. It may take a few attempts but it bypasses the gearcheck. It also requires a decent healer to keep up the mages. The tank shouldn't be getting hit too hard in comparison.

Alternative Strategy 2

Because Shaffar deals almost exclusively magical damage, a Warlock can effectively tank the boss while still dealing a large amount of damage through DOTs and holding aggro by using Searing Pain as much as possible (a Balance Druid or Elemental Shaman might also be able to pull this off with enough HP, although aggro might be an issue due to spell pushback reducing their DPS.) In this case, the "conventional" tank can be used to hold aggro on the adds while melee DPS kills the adds and ranged DPS attacks the boss, or the "tank" can switch to DPS gear and simply act as melee DPS to help kill adds as quickly as possible.

This is actually a fairly simple strategy to execute, as it avoids much of the confusion caused by melee tanking/DPS on the boss. As long as adequate healing can be maintained on the Warlock, the boss can be killed quickly.

Alternative Strategy 3

Similar to that of killing the adds, another approach is to continuously kill the Ethereal Apprentice adds until Nexus-Prince Shaffar has run out of mana. At this point, he is likely to be at greatly reduced health and unable to summon Ethereal Apprentice adds until he has regenerated enough mana to do so.

This strategy relies more on your healer's mana regeneration. If you attempt Shaffar with this method, prepare to be fighting for approximately five to seven minutes. Bring potions/food if necessary.

Killing the Adds

In heroic mode, the beacons transform into apprentices very fast, and the apprentices are at full health even if the beacon was nearly destroyed. It may be more effective to simply ignore the beacons until they transform, and then burn down the Apprentices as quickly as possible. While the apprentices have more health, any damage done to a beacon that is not destroyed before the apprentice spawns is completely wasted, and the health difference is small enough to potentially make it worthwhile. It is still recommended to focus fire at the start of the fight to destroy at least one of the initial beacons before it can spawn. It is also beneficial to have the tank get aggro on all the initial beacons so they do not attack your healers early in the fight.

Further Notes

These points may make the fight easier with the Kill Adds strat. Especially if you have wiped a few times and do not seem to be making progress:

If you have a Mage or Warlock, they can use their Pyroblast or Soul Fire spell on one of the beacons at the start of the fight. The spells have a long cast time, and can be started before the boss is actually engaged. This will make the first beacon kill extremely quick.

It is very helpful to have all DPS focus on killing the initial wave of beacons/adds before starting to DPS Shaffar. This eliminates a lot of the confusion at the beginning of the fight, as well as giving the tank time to build aggro.

There are tradeoffs to having melee or ranged DPS on the adds. Melee DPS is more effective against the adds than the boss, since they are not constantly being taken out of melee range or being frozen. However, ranged DPS can generally focus-fire the adds down faster by assisting off a specified group member, reducing the overall amount of damage the group is taking. If your healers are having trouble keeping the group alive because the adds are living too long, putting ranged DPS on them can help.

Use short cooldowns and potions early; in a successful attempt you will generally get to use 2-minute cooldowns twice if you use them early in the fight.

Shaffar does not have that many hit points; if he gets below 20-25% health but your healers are running out of mana, you may be able to kill him by going all-out DPS and simply ignoring the adds. Note that the adds do not despawn after his death, but it doesn't really matter if the group wipes at that point.