DM Advice - Lair Actions within Pathfinder

[Myrmidon369]

So I'm running Way of the Wicked, we're on book 4 and getting ready to fight Eiramanthus, an ancient copper dragon. The party consists of all level 14, an alchemist, sorcerer, bloodrager, antipaladin, a cleric, and two npcs (level 13 shaman necromancer and Grumblejack, level 13 Ogre/Two-Handed Fighter). Now, my party is pretty optimized, steam rolling through encounters without my tweaking. I think with a houserule allowing a Antimagic Field to extend 10ft from his entire party, that alone will surprise the party, but I want the fight to be memorable. The location is very bland, simply a large dome, 140x140ft.

I have been adding in Lair Actions from 5e to spice things up a bit, such as adding minions or spell effects that can modify the battlefield a bit. Since Eiramanthus is a planar traveler, I was thinking of having his dome teleport from one plane to the next every four rounds or so. But the thing is, I have never ran anything involving the other planes and realms and am sorely inexperienced in it.

So my question is, how should these lair actions look like? Which planes should I use? His consorts come from water, nature, and a world at war. Pretty vague really. I was thinking of 1st Round - Plane Shift, 2nd Round - Minions arrive, say elementals; 3rd Round - Some kind of effect related to the plane; and 4th Round - Plane shift again?

[Kurald Galain]

While I really like your idea, I think that at level 14 with an optimized party, combat will be over in one or two rounds; so your effect after four rounds will simply not happen.

[Myrmidon369]

While I really like your idea, I think that at level 14 with an optimized party, combat will be over in one or two rounds; so your effect after four rounds will simply not happen.

I would agree normally. He knows they're coming and is going through his horde and using some potions and equiping a few wonderous items, such as a Ring of Blinking. He'll have one consort, a CR 15 dryad with him. So I was hoping with this and changing to at least one different plane would cause the battle to last longer. He'll also be throwing up his Antimagic Field and have it extend around his body 10ft completely.

If someone where to have a plane shifting battlefield, what would you use? What kind of enviroment effects would there be? Minions? What is something interesting a dragon could do there?

[AllanniaNevini]

I would have the dragon be buffed more than the story has so it would be a challenging encounter. I've had it happen that a fight that needed to last 5 minutes game time only lasted 20 seconds. I would make it so that time moves slower so the combat takes more time. Have the room shift every two rounds and have environmental hazards in each room. For example: in the fire relm have the floor catch on fire randomly. Have the room shift through several elements including shadow.