NiM Calphayus

What we bring:

2 Tanks - I recommend using at least one Vanguard with the Friendly Pull w/Grapple Utility.  (We use 2 Vanguard Tanks as a preference for this fight).
4 DPS - We use: 1 Sentinel (Watchman) | 1 Scoundrel (Ruffian) | We prefer 2 strong burst specs to fill out the final two spots, but any DPS with good output fills the roster out perfectly.
2 Heals - Roles are flexible, we use a sage / Commando

We begin this engagement in the exact same manner as we do in Hard Mode.  To recap with our strategy, we stand on the "root" at the front entrance to the room.  Our tank taunts the boss and scoots back, placing their back against the wall.  The entire Ops team stack in right behind Calphy and begins to burn the boss.  One player MUST stand out.  We have a healer do this.  The healer stands on one of the front fountains to bait out the BIG red circle that will come out almost immediately after the boss is pulled.

BIG RED CIRCLE - Must be baited away from the group by one player.  In NiM mode, the effects of this circle's root will keep players from being able to move to the portals when they become active.  If the bait player does not move away quickly enough, or the group does not stack it and the circle ends up on the raid team, it will result in a wipe.

Inevitability - Same Tank Mechanic as in Hard Mode.  When Calphy channels it and hits the active tank, the Tanks must swap, or the active tank will die from the applied debuff.  The Tank receiving the Debuff needs to take extra caution when stacking back into the group behind Calphy.  They should make certain they do not get cleaved, or it will kill them instantly.  The same goes for the team stacked behind Calphy, if they inadvertently get clipped by this channel and get hit again, they too will die.

Shortly after the boss hits 80%, he will jump back to his starting location at the throne and begin to channel.  This is the exact same mechanic as in Story and Hard Mode, however, now we only have 5 seconds to get to our portals, or we are left behind and die.  We use Transcendence from our sentinel here to help with movement here.  The team should be watching and be ready to run as soon as he jumps away.

Here is our preferred fire team Split for the Portals in NiM Mode

Blue Portal (LEFT) - 1 Tank | Watchman | Healer (3 Players)

Orange Portal (RIGHT) - 1 Tank | Rest of DPS | Healer (5 Players)

Example of moving to the seed and attacking the boss.

The Orange team has the real DPS check and is why we send 3 DPS to that side.  It can certainly be done with 2 DPS, but from my experience, 3 is what is needed.

Orange team is responsible for 2 things:

1) Calling out to the blue team where to plant the seed.  The plant area will be glowing.  In the above example, the orange team would call out "Back Right" for seed planting.  Blue team should confirm as planting incorrectly will wipe the team.  (Recommend Blue team reverifying this intel as they push Calphy to shielded)

2) Killing the Despoiler before it nukes you with mass affliction (uncleansable).

In NiM, the add is SUPER dangerous.  If it is allowed to finish its channel, it will most likely wipe the group.  It has been my experience that the DoT will overwhelm the healer and kill party members.  When it spawns, the entire fire team focuses it down quickly  (tank and healer as well).  [Note that 2 of these spawn in 16 NiM Mode, we use a 4 Blue | 6 Orange split and coordinate killing of them 1 at a time].

That is it for orange team.  Multiple of these Despoiler adds will spawn, so be ready and call attention to them when they come in. 

Once Caphy is pushed to 80% by the Orange team, he will jump and smash a crystal.  We try to give Blue team time to DPS the Crystals to lower their HP, making it easier to pass the DPS check when the orb appears.  Again, there is no enrage here, so take your time and wait for the call.  We have the crystal's low enough by the time we DPS the boss to 80% after many reps on the fight and do not need to hold up now.  You may want to initially give your team time to get good at it, then push for speed (for future timer runs).

Blue team should start smashing crystals as soon as they get them in the room, taking care not to destroy any of them (potentially botching the run).

Orange Team can call out the leaps in advance.  The boss smashes a crystal at 80%, 50% and 25% of its HP (on the Orange side).  Double check all calls made and be sure as a DPS you are hitting the correct Crystal.