Pyramid
A Pyramid is a cycle of cards meant to represent something "building up" until it has reached a point of triumph, where a "capstone" card is then played that offers great rewards for spending all the effort constructing it. Pyramids were first introduced by the Player's Council in set The Pelennor Fields (V3).
There were two pyramids introduced in V3, a Beacon 
Gondor/
Rohan Free Peoples pyramid, and a Twilight 
Sauron/
Ringwraith Shadow pyramid. Each pyramid has the same basic construction as follows:
- A single triple-dot Tier 1 card that makes up the base of the pyramid, offering ways to recycle other pyramid pieces from the discard pile
- Multiple double-dot Tier 2 cards with the same title but differing subtitles, which offer various ways to use your pyramid pieces as resources for a variety of effects.
- A unique Capstone card that is unhinderable, undiscardable, and provides some enormous effects that pay off for all your effort (and deck space) put into the pyramid.
The Beacons
The Free Peoples pyramid represents the lighting of the beacons of Gondor, and so as more and more of them are lit, the signal eventually reaches Rohan, where Théoden and his people march to Gondor's aid. A major focus of this cycle is blurring the lines between Gondor and Rohan, permitting the two cultures to work with one another much more closely.
Tier 1: War-beacon
Tier 2: Northern Signal-fire
Capstone: Gondor Calls for Aid!
Cover of Darkness
In contrast, the Shadow pyramid represents Sauron's encroaching storm-clouds, which slowly cover up the Sun until all is darkness. Once all light is blotted out, every major Shadow race gains a new dark keyword, and Sauron himself becomes much easier to summon to the battlefield.
Tier 1: Ominous Sky
Tier 2: Cover of Darkness
Capstone: Endless Night
