Encounter-specific Details, Actions and Tactics
Olm's Specific Quirks:
Each of Olm's hands and his head are treated as different creatures, with separate hit point pools, and stats. Olm's left and right hands do not roll initiative, instead, they enter initiative in a staggered fashion. For example, if players 1-4 and Olm's head rolled initiative, leading to the initiative order "1 Head 2 3 4", the left and right hand would enter initiative as follows: "1 Head 2 Left hand 3 Right hand 4". This is to prevent all of the enemies acting simultaneously.
Mental effects that target a single creature (e.g. Demoralize) can be used on any of Olm's three components, and would only effect that component. Such an effect would likely target Olm's head in the narrative, but can mechanically be applied to any of his three component stat blocks. If you like, you could try to narratively justify it, e.g. Demoralizing his left hand by shouting at Olm's head about the grime under the talons on his left hand. For all purposes other than the narrative (determining range, line of sight, considering buffs/debuffs on some of Olm's components, etc), such effects are considered to be targeting "Olm's Left Hand" as if it were a completely separate creature to Olm's Head or Right Hand
When one of Olm's hands is reduced to one of the listed hp thresholds, it recoils and retracts, becoming untargetable and ceasing to take actions. This retraction does not provoke reactions, and any excess damage beyond the hp threshold is lost. Olm's hands also cannot be healed beyond an hp threshold that has already been passed.
Once both hands have retracted, Olm's head also retracts, and at the end of the current turn all 3 "components" of Olm reappear on the opposite side of the arena. This marks the transition between phases 1, 2 and 3 (which influences which of Olm's abilities are available).
When a hand is reduced to 0hp, it is removed from the encounter. When both hands are reduced to 0hp, replace the Great Olm - Head statblock with the Great Olm - Enrage Phase statblock. The fight ends when the Enrage Phase is reduced to 0 hit points.
Olm's Tactics:
General tactics: The Great Olm is clever, and will prioritize (1) special attacks that can hit large clusters of creatures and (2) focusing on priority targets (e.g. creatures revealed to be healers, and low health creatures). However, he does not hit creatures once they have been knocked out. As his only precise sense is hearing, with a range of 40ft, any creature outside of this range (as measured from his head) is Hidden to ALL of Olm's statblocks
Right hand: Unless using Restore Vitality, always spends 2 actions using Acidic Blast, Burn With Me or Crystal Bombs. Its final action is used on a Crush attack or athletics manoeuvre against a creature in melee if possible, otherwise Taking Cover behind the ledge to gain standard cover.
Left hand: Unless using Restore Vitality, always spends 2 actions using Crystal Burst, Lightning or Warp. Its final action is used on Demoralize if possible, otherwise attempting to Aid an upcoming action from Olm's head or right hand (If attempting to aid by bolstering itself: DC 26 Occultism, +3 on critical success) (If attempting to aid by distracting the party: Deception check against the Perception DC of the creature it is trying to distract, +2 on critical success).
Head: Prioritizes targeting creatures within range of its precise hearing. Always spends 2 actions making some combination of Crystal Shard or Air Blast attacks, and the final action on Orb of Force. If deviating from this routine (e.g. using an action to recover from sickened, or if slowed), the second Crystal Shard/Air Blast of the round is the "lowest priority" action.
Room Description/Flavor Text
Preparation Chamber:
Descending a stone staircase, you find yourselves in another hallway. Before you is a giant rune hovering in the air, glowing bright green. Passing through, you find yourselves feeling restored, as you all gain the benefits of a long rest, and emerge into a chamber with another, similar rune directly in front of you. Next to the rune, you see inscriptions carved into the cave walls.
Olm's Arena:
Passing through the great rune, you see chasms yawning into darkness on either side of you, as you enter a walkway fit for giants. Crystal outcroppings line the walls, glowing with green light and reflecting off each other, creating strange, fractal-like patterns. A loud *thud* shakes the floor of this walkway, and the bones of the *ants* that the Great Olm has sensed traversing it. A horrid scraping, crunching noise echoes through the cavern, as a gargantuan hand appears, gripping the ledge of the chasm, nails tearing through the stone. Another thud, another series of crunches and scrapes, herald the arrival of another hand. And between them, the head of the Great Olm emerges. An alabaster-white draconic face and neck, covered in crackling green energy, dripping acid, horns made of the very crystal that has dotted this entire complex of caves. Its milky eyes seem unable to focus on any of you, but you feel an urge to shrink before its presence nonetheless. Roll initiative.
Recall Knowledge DCs
DC 28 Arcana, Nature
DC 26 Perception (only to identify its blindness and/or its limited sensory range)
DC 23 Aquatic/Ocean/Sailing/Fishing/Dragon Lores (due to his presence in folk tales)
