The Ninth World (Homebrew), The Princes of the Apocolypse
Earthen Defeat. When Marlos drops to 0 hit points, his body transforms into mud and collapses into a pool. An earthquake also shakes the area for a few minutes. Anything he is wearing or carrying is left behind. Once defeated a small bag will be left behind with a tag signed "The Blue the Medusa". The bag is a gift from Psyrethelia for killing Marlos. It is Oddy Bodden’s Stupendously Amazing Magical Dice of Treasures Unimagined and Horrors Rather Left Undiscovered! (see DCC Hubris setting for details, if not available, use the deck of many things). Earth Passage. Marlos can move in difficult terrain composed of anything made from earth or stone as if it were normal terrain. He can move through solid earth and rock as if it were difficult terrain. If he ends his turn there, he is shunted into the nearest space he last occupied. Legendary Resistance (3/Day). If Marlos fails a saving throw, he can choose to succeed instead. Mythic. When Marlos's Giant is killed his poison damage becomes radiation damage. He also gains access to new attacks (marked with the mythic tag) and Legendary Actions. Petrifying Gaze. When a creature that can see Marlos’s eyes starts its turn within 30 feet of him, Marlos can force it to make a CON saving throw if Marlos isn’t incapacitated and can see the creature. If the saving throw fails by 5 or more, the creature is instantly petrified. Otherwise, a creature that fails the save begins to turn to stone and is restrained. The restrained creature must repeat the saving throw at the end of its next turn, becoming petrified on a failure or ending the effect on a success. The petrification lasts until the creature is freed by the greater restoration spell or other magic. Unless surprised, a creature can avert its eyes to avoid the saving throw at the start of its turn. If the creature does so, it can’t see Marlos until the start of its next turn, when it can decide to avert its eyes again. If the creature looks at Marlos in the meantime, it must immediately make the save. If Marlos sees himself reflected on a polished surface within 30 feet of him and in an area of bright light, Marlos is, due to his curse, affected by his own gaze.
Multiattack. Marlos makes three melee attacks, one with his snake hair and two with Ironfang. Snakey Hair. Melee Weapon Attack: 1d20+9 to hit, reach 15 ft., one target. Hit: 7 ( 1d8+5 ) piercing damage plus 14 ( 4d6 ) poison damage and, the target makes a CON saving throw, on a natural 1 the target dies. Marlos can pull the target up to 5 feet closer to him if it is a Medium or smaller creature. He may fling a target 5 feet instead (if using zone combat, he pulls a target to his zone or pushes a target out of his zone). The target is also grappled (escape DC 17). Until this grapple ends, the target is restrained and takes 15 ( 3d6+5 ) bludgeoning damage at the start of each of its turns, and Marlos can’t constrict another target. Ironfang. Melee or Ranged Weapon Attack: 1d20+9 to hit, Hit: 9 ( 1d8+5 ) piercing damage plus 13 ( 3d8 ) thunder damage. The target's non-magical items must make a DC 10 saving throw or be destroyed by the attack. If used as a ranged weapon, it immediately returns to Marlos's hand.
Once The Long-Arm Centipede Giant (Petrification) is killed Marlos gains the listed legendary actions. He has 1 legendary action per two PCs he is facing with a minimum of 3.
In the Earth Node or Fane of the Eye
When the Temple of Black Earth is threatened, Marlos Urnrayle retreats to the Black Geode, the earth node. Within this node, Marlos gains one additional use of his Legendary Resistance trait.
Lair Actions
If Marlos is in the earth node while Ogrémoch isn’t, Marlos can take lair actions and has a challenge rating of 12. On initiative count 20 (losing initiative ties), Marlos uses a lair action to cast earthquake without using components. As long as he maintains concentration on earthquake, initiative count 20 is the start of Marlos’s turn for the purpose of the spell. He can take no other lair actions while concentrating on earthquake. Any creature knocked prone must spend its entire movement and action getting up.
Marlos’s second option for a lair action is to draw power from the earth node to heal. When he does so, he regains 30 ( 6d8+3 ) hit points.
Servant of the Eye
A multicored and oily portal/hole will appear from the roof which slowly expands as the mute-tentacled horror known as Servant Of The Eye (Greater) pulls itself through. While the Servant Of The Eye (Greater) lives, Marlos can not be attacked via melee (if using zone combat, creatures can't enter the central zone where Marlos and the altar are).
Timer
Each time the timer ticks down to 1 a bane is added to the saving throw against Marlos's Petrifying Gaze attack. This starts at 1d4 and increases until it can not be resisted when it gets to the d20.
ROCK ARMOR half plate + 1, rare 3,000gp/750xp While wearing the armor, you can walk along any earth, stone, or rock surface as if it were flat (including up walls and across ceilings), and no rocky terrain ever counts as difficult terrain. The target can smash foes with his earthen limbs, which attack, threaten foes, and deal 1d6 damage. Once a day, you can encircle your body with rocks which block incoming damage. The armor provides 10 temporary hit points. The wearer can decide to detonate the armor; all creatures within 5 feet of you take 10 bludgeoning damage (no save).
Temple of Elemental Evil, The Greater Temple, Fane of the Eye, Earth Node