Monster: Aerundora, the Guardian of Coral Isle

Adam Pate

February 2, 2025

Monster

Aerundora, the Guardian of Coral Isle

Huge Dragon Turtle (Protector) , Neutral Good

Armor Class: 20 (Natural Armor)

Hit Points: 265 (20d12 + 120)

Speed: 30 ft. (land), 60 ft. (swim)

Challenge Rating: 10 (5,900 XP)

STR	DEX	CON	INT	WIS	CHA
26	11	20	2	16	18

Saving Throws: Strength +14, Constitution +11, Wisdom +9, Charisma +10

Skills: Perception +9, Nature +5

Damage Vulnerabilities: none

Damage Resistances: none

Damage Immunities: Poison, Psychic

Condition Immunities: Charmed, Frightened, Paralyzed

Senses: Truesight 120 ft., passive Perception 19

Languages: Aquan; understands Common but cannot speak.

Spellcasting

Spellcasting. The Tidal Beast, Aerundora, is a 6th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 18, +10 to hit with spell attacks). Aerundora has the following spells prepared:

Cantrips (at will): *Druidcraft, Shape Water, Guidance*

1st level (4 slots): *Thunderwave, Create or Destroy Water, Fog Cloud*

2nd level (3 slots): *Gust of Wind, Misty Step, Moonbeam*

3rd level (3 slots): *Call Lightning, Water Breathing*

4th level (3 slots): *Summon Elemental, Control Water*

5th level (2 slots): *Conjure Volley, Maelstrom*

Aerundora’s spells reflect its connection to the ocean and its role as a guardian of the seas. It can use spells like *Control Water* strategically to influence the battlefield, creating advantageous conditions while protecting the aquatic life around it. In combat, it often starts by casting *Fog Cloud* to obscure its location and uses *Thunderwave* to push back intruders. Special notes about Aerundora’s spellcasting include that it can only cast spells while in the water or when submerged, harnessing its connection to the ocean depths.

Actions & Abilities

Multiattack: Aerundora makes three attacks: one with its Bite and two with its Horns.

Bite: *Melee Weapon Attack:* +14 to hit, reach 10 ft., one target.
*Hit:* 34 (4d12 + 8) piercing damage.
**Effect:** If the target is Medium or smaller, it must succeed on a DC 20 Strength saving throw or be grappled (escape DC 20). The grappled target is restrained until it escapes.

Bludgeon: *Melee Weapon Attack:* +14 to hit, reach 10 ft., one target.
*Hit:* 40 (4d12 + 8) bludgeoning damage.
**Effect:** The target must make a DC 18 Constitution saving throw. On a failed save, it is stunned until the end of its next turn.

Horn Charge (Recharge 5-6): *Melee Weapon Attack:* Aerundora charges forward in a straight line (up to 30 feet), passing through any creature’s space.
Each creature in this line must make a DC 20 Strength saving throw, taking 52 (6d12) bludgeoning damage on a failed save or half as much damage on a successful one.
**Effect:** Creatures that fail the save are also knocked prone.

Surge of the Tides (Recharge 5-6): Aerundora channels the essence of the sea, creating a powerful whirlpool at a point it can see within 60 feet.
All creatures in a 30-foot radius must succeed on a DC 18 Strength saving throw or take 45 (10d8) cold damage and be pulled 15 feet toward the center of the whirlpool.
On a successful save, the creature takes half damage and is not pulled.

Coral Spire (Recharge 6): Aerundora summons sharp coral spikes from the seafloor in a 20-foot radius around itself.
Each creature in this area must make a DC 18 Dexterity saving throw, taking 27 (6d8) piercing damage on a failed save or half on a successful one.
The area becomes difficult terrain for 1 minute.

Oceanic Blessing (Recharge 3-6): Aerundora channels protective magic, granting one ally within 60 feet advantage on their next attack roll and temporary hit points equal to 10 + Aerundora’s Constitution modifier.
**Effect:** The ally retains these temporary hit points until they are depleted or until the end of the encounter.

Solar Glare: Aerundora releases a burst of dazzling light from its eyes; all creatures in a 30-foot cone must succeed on a DC 18 Constitution saving throw or be blinded until the end of their next turn.

Summon Seas: Aerundora calls forth a wave. Each creature in a 20-foot radius must make a DC 18 Strength saving throw, taking 22 (4d10) bludgeoning damage on a failed save and being knocked prone, or half damage on a success.

Coral Fortress (Costs 2 Actions): Aerundora raises a barrier of coral from the seabed, creating difficult terrain (15 ft. radius) around it for 1 minute.
Creatures within this area have disadvantage on melee attacks and must succeed on a DC 18 Dexterity saving throw or be restrained until the barrier is dispelled or expires.

Legendary Resistance (3/Day): If Aerundora fails a saving throw, it can choose to succeed instead.

Appearance

Physical Description of Aerundora, the Guardian of Coral Isle

Size and Shape: Aerundora is a colossal creature, measuring approximately 40 feet in length and towering about 20 feet high at the peak of its shell. Its body resembles a floating island, broad and rounded, with a massive dome-like structure that supports its intricate coral-encrusted shell. The sheer size of Aerundora conveys both tranquility and intimidating power.
Coloration: The creature’s shell displays a mesmerizing gradient of deep blues, vibrant teals, and soothing greens that mimic the colors of the surrounding tropical waters. Under sunlight, its surfaces glisten with hints of golden luminescence, while the coral formations add splashes of bright oranges, purples, and pinks, creating a breathtaking array of colors that constantly shifts with the tides.
Texture and Surface Features: Aerundora’s skin is covered in tough, scaly textures, providing it with formidable natural armor. The scales, while rough and resilient, hold a unique sheen due to their bioluminescent properties, allowing them to glow softly at night. Triangular barnacle-like protrusions, pulsating with radiant hues, cling to its limbs and shell, singing soothing melodies when the creature is at ease.
Facial Features: Aerundora’s face is distinctively regal and powerful, featuring large, expressive eyes made of an enchanting molten gold. Its eyes are framed by creased skin that emphasizes its ancient wisdom. The mouth is wide and capable of delivering a crushing bite, filled with rows of sharp, conical teeth meant for tearing through flesh. The most striking aspect is its two spiraled horns, which spiral upwards, adorned with iridescent gems and often shimmering with magical energy.
Limbs and Appendages: Aerundora possesses six robust limbs that resemble mighty anchor chains. Each limb is thick and muscular, reminiscent of the strength needed to navigate deep ocean currents. The limbs taper into powerful flippers, which aid in swift swimming, while also allowing it to strike with impressive force when required. The flippers are also adorned with bioluminescent barnacles, creating additional visual flair underwater.
Special Features: A unique characteristic of Aerundora is the vibrant coral formations sprawling majestically across its carapace, which transform based on its emotional state or the environment it finds itself in. During moments of calm, the coral may flutter gently in the current, but when agitated, it becomes rigid and potentially lethal. The shimmering horns hold arcane properties, capable of channeling storms and tidal forces.
Posture and Movement: Aerundora maintains a slightly hunched but commandingly regal posture while at rest but is capable of rising gracefully, seeming to glide rather than swim when moving through water. Its movements are a mesmerizing mix of fluidity and power, showcasing both the grace of an ancient guardian and the ferocity of a fierce protector when threatened.
Additional Notable Traits: Aerundora’s shell is not merely for protection; it tells the story of the oceans through its intricate coral patterns and glowing markings. When it senses threat, the markings on its shell pulse ominously, creating an ethereal glow that reflects its connection to the ocean’s magic. At night, its bioluminescent qualities intensify, transforming Aerundora into a beacon of beauty and dread, an ethereal guardian amidst the waves.

Tactical Information

Tactical Information: Aerundora, the Guardian of Coral Isle

Combat Behavior:

Aerundora is a guardian first and a combatant second. Its behavior in combat reflects both its role as a protector and its overwhelming power. The following tactical behavior outlines how Aerundora engages in combat, ensuring players encounter an exciting and challenging experience.

Initial Combat Strategy:

Defensive Positioning: Aerundora will initially position itself between threats and its hatchlings or allies, using its massive size to block access. It prefers to use its natural terrain to its advantage, like shallow waters or coral formations, making the most of its Protective Surge ability to grant temporary hit points to allies.
Assess Threats: Aerundora will begin combat by assessing the threat level of intruders through perception checks, focusing on the ones who pose immediate danger to its progeny or home base. It can recognize skilled adversaries by their weaponry or spells and will prioritize them.

Attack Patterns:

Multiattack Focus: Aerundora will utilize its Multiattack feature to hit the closest threat with its Bite or Bludgeon, alternating between crushing physical attacks and maintaining an aggressive stance to ward off multiple attackers. It prioritizes foes that spread out to attack its allies.
Horn Charge Utilization: When surrounded or outnumbered, Aerundora will strategically use its Horn Charge ability. It will target tightly-packed enemies to maximize damage, making sure to announce its charge as intimidating, effectively providing players a brief opportunity to respond strategically.
Summon Seas: In the event that players attempt ranged attacks whilst maintaining distance, Aerundora will employ its Summon Seas legendary action to disrupt formations. This keeps foes from effectively ranged attacking without concern while showcasing its control over the battlefield.

Defensive Actions:

Retreat to Coral Fortress: If Aerundora finds its health dwindling (after using its Protective Surge), it will retreat to a resource-rich area (or invoke its Coral Fortress ability) to call on defensive terrain that can restrict enemy movement, appearing to call the very ocean to its aid.
Legendary Actions: Aerundora will often use its legendary actions after enemy turns, strategically employing Solar Glare to hinder spellcasters or ranged attackers who threaten it, forcing them to either disperse or become blinded. It may reserve Coral Fortress for when multiple targets are closing in.

Narrative Interactions:

Aerundora’s interactions with players can lead to extraordinary storytelling moments, depending on players’ actions and intentions. The following outlines potential narrative outcomes based on player engagement:

Non-Hostile Encounters:

Guardianship Role: If players approach in a non-aggressive manner, perhaps offering gifts of food or special artifacts honoring the sea, Aerundora can be engaged in conversation. Through deep wisdom conveyed by its truesight, it may share knowledge of the ocean’s magic, grant quests of protection for its offspring, or even impart unique blessings upon the players.
Rituals of Respect: If players perform rituals honoring the sea (perhaps by invoking songs of the ocean, offering seashells, or cleansing water), Aerundora may become more trustful and offer insight into the balance of nature, revealing possible dangers to Coral Isle.

Hostile Interactions:

Menace to Combatants: If players attack immediately, Aerundora’s initial actions will be defensive warnings. It will roar and create swells in the water, manifesting environment effects like temporary tidal waves. This makes clear the seriousness of their actions, promoting players to reconsider aggressive tactics.
Righteous Wrath: Should combat escalate with relentless aggression, Aerundora is likely to become a symbol of nature’s fury. In the midst of combat, it may uplift nearby coral and plant life to assist it, showcasing the interconnectedness of nature. The players then may feel not only the wrath of a guardian but the entire ecosystem against them.

Resolution:

End of Conflict: Depending on the choices players make during or after the encounter, Aerundora may offer players a chance for peaceful coexistence. It might gift a written blessing or magical item infused with oceanic energy, leading to further quests or recognition among local tribes as heroes or protectors of nature.

Through strategically leveraging its combat behaviors and narrative interplay, Aerundora not only functions as a formidable challenge but also as a rich story element that evolves based on player decisions, ensuring each encounter is memorable and dynamic.

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