Caerosivous, The Forest's Heart, Shaker of The Earth, Guardian of The Green Nexus, Forsaker of The Mother

According to the Old Lore this a great wood that exists in a place between places to which ancient greens can go at the end of their life. Where they may choose to bond with the land itself and join the collective knowledge of the Nexus that has been created there.  This place is said to be drunk with the power, wisdom, and spirits of these dragons.  A place full of boundless growth and fertility, where the flora and fauna are wilder and fiercer than anywhere else in the multiverse. This great wood is steeped in the energies of the Fae Wilds, The Elemental Plane of Earth, and something deeper more wild and primordial that is uniquely its own. With each dragon that brings itself to this place that ends its life in this way adds its wisdom, its power, and its energies to that of the land. 

This burial ground, this Nexus of The Green is a place of great importance to all green dragons and perhaps the only thing they might ever agree to work on cooperatively as a species.  To that end they charge the greatest and most powerful amongst them to become its guardian. This guardian becomes bonded to the Nexus through its heart. This bond infuses the dragon with power and size it would never naturally know and grants it extreme longevity. This bonding grants the dragon the access to the knowledge of the Nexus but curses it to be bound to the land itself, unable to travel more than 100 miles from the nexus. When the dragon begins to near the end of its incredibly extended life it will call to another Green worthy to take its place. When this heir arrives the guardian does battle with the prospective heir. If their heir wins, they claim the heart and become the new guardian. If the Guardian wins, they claim the heart of the lifeforce of the perspective heir and extend their life even further. Caerosivous has called to nine perspective heirs, and is nearing his time to call for a tenth. 

The most cunning and treacherous of true dragons, green dragons use misdirection and trickery to get the upper hand against their enemies. A green dragon is recognized by the crest that begins near its eyes and continues down its spine, reaching full height just behind the skull. Although Greens tend to be smaller than the rest of their chromatic cousins, Caerosivous is a truly colossal dragon. Standing 90 feet tall at the shoulder with a total length nearly twice that and a wing span of over 200 feet. He sleeps decades if not centuries between his bouts of wakefulness and when he sleeps its not uncommon for him to become cover in dirt and vegetation to the point that he can be mistaken for a great hill or small mountain. Caerosivous is a dangerously clever, and frighteningly wise dragon he plans and manipulates in a way that would make the rest of the greens envious. He will beguile and trick his enemies before he'd do battle with them. Yet if pushed, he will fight and things around him will die in his displeasure. 

Caerosivous dwells at the heart of a arboreal valley with an area of over 7500 square miles that is flanked on three sides by a mountain range that forms the shape of a dragon's head. This massive old growth forest is completely wild and untamed with very very sparse pockets of settlement. The trees are massive many with heights in excess of 150 feet. The plants of this forest are thorny and frequently poisonous, some have become carnivorous and actively predatory. The Fauna is similarly altered by the presence of the Nexus and Caerosivous themself. These creatures will be at least one size category larger than their mundane cousins, many herbivores will be omnivores, and omnivores have frequently become obligate carnivores. The overwhelming majority of the flora and the fauna of the valley are poisonous, venomous, or both. This valley is a clearly dangerous and inhospitable place yet it is not without its own sapient denizens. Within the forest exists a number of settlements whos denizens worship the guardian of the Nexus as a god. These denizens are hard, aggressive, and intimidating people who distrust outsiders to a xenophobic extent. Caerosivous considers these peoples to be a fundamental part of their hoard and some of their most favored trinkets. 

Lair Actions

On initiative count 20 (losing initiative ties), the dragon takes a lair action to cause one of the following effects; the dragon can’t use the same effect two rounds in a row:

• Grasping roots and vines erupt in a 20-foot radius centered on a point on the ground that the dragon can see within 200 feet of it. That area becomes difficult terrain, and each creature there must succeed on a DC 20 Strength saving throw or be restrained by the roots and vines. At the end of each of their turns, a creature restrained this way takes 8 (2d6) piercing damage from thorns creatures damaged by the thorns take 12 (3d6) poison damage and must then make a DC 18 Constitution saving throw those that fail gain the poisoned condition. If the creature is already poisoned, failing this save causes the creature to gain 1 level of exhaustion.  A creature can be freed if it or another creature takes an action to make a DC 20 Strength check and succeeds. The roots and vines wilt away when the dragon uses this lair action again or when the dragon dies.
• A wall of tangled brush bristling with thorns springs into existence on a solid surface within 200 feet of the dragon. The wall is up to 100 feet long, 30 feet high, and 10 feet thick, and it blocks line of sight. When the wall appears, each creature in its area must make a DC 20 Dexterity saving throw. A creature that fails the save takes 18 (4d8) piercing damage and is pushed 5 feet out of the wall’s space, appearing on whichever side of the wall it wants. A creature damaged this way takes an additional 12 (3d6) poison damage and must then make a DC 18 Constitution saving throw those that fail gain the poisoned condition. If the creature is already poisoned, failing this save causes the creature to gain 1 level of exhaustion.  A creature can move through the wall, albeit slowly and painfully. For every 1 foot a creature travels through the wall, it must spend 4 feet of movement. Furthermore, a creature in the wall’s space must make a DC 20 Dexterity saving throw once each round it’s in contact with the wall, taking 18 (4d8) piercing damage on a failed save, or half as much damage on a successful one, a creature damaged this way takes an additional 12 (3d6) poison damage and must then make a DC 18 Constitution saving throw those that fail gain the poisoned condition. If the creature is already poisoned, failing this save causes the creature to gain 1 level of exhaustion. Each 10-foot section of wall has AC 5, 45 hit points, vulnerability to fire damage, resistance to bludgeoning and piercing damage, and immunity to psychic damage. The wall sinks back into the ground when the dragon uses this lair action again or when the dragon dies.
• Magical fog billows around one creature the dragon can see within 200 feet of it. The creature must succeed on a DC 20 Wisdom saving throw or be charmed by the dragon until initiative count 20 on the next round and perceive their party members as enemies attacking the closest party member to themselves. a creature charmed this way chooses to automatically fail the save against any spell Caerosivous casts upon them. 
• An 80 foot deep, pit with a 10 foot radius lined with barbed and thorny vines opens beneath a creature the dragon can see within 200 feet of it. The creature, and any other in the area of the pit, must make a DC 20 dexterity save or fall into the pit. A creature that falls into the pit takes 8 (2d6) piercing damage 12 (3d6) poison damage and must then make a DC 18 Constitution saving throw those that fail gain the poisoned condition. If the creature is already poisoned, failing this save causes the creature to gain 1 level of exhaustion. The pit ejects its contents, inflicting its damage again, and closes if the dragon uses this lair action again

Regional Effects

The region containing a legendary green dragon’s lair is warped by the dragon’s magic, which creates one or more of the following effects:

• Thickets form labyrinthine passages within 20 miles of the dragon’s lair. The thickets act as 30-foot-high, 15-foot-thick walls that block line of sight. Creatures can move through the thickets, with every 1 foot a creature moves costing it 4 feet of movement. A creature in the thickets must make a DC 15 Dexterity saving throw once each round it’s in contact with the thickets or take 8 (2d6) piercing damage from thorns creatures damaged by the thorns take 12 (3d6) poison damage and must then make a DC 18 Constitution saving throw those that fail gain the poisoned condition. If the creature is already poisoned, failing this save causes the creature to gain 1 level of exhaustion. 
  Each 10-foot-cube of thickets has AC 5, 30 hit points, resistance to bludgeoning and piercing damage, vulnerability to fire damage, and immunity to psychic and thunder damage.
• Within 20 miles of its lair, the dragon leaves no physical evidence of its passage unless it wishes to. Tracking it there is impossible except by magical means. In addition, it ignores movement impediments and damage from plants in this area that are neither magical nor creatures, including the thickets described above. The plants remove themselves from the dragon’s path.
• Animals with an intelligence of less than 12 within 10 miles of the dragon’s lair serve as the dragon’s eyes and ears. Deer and other large game are strangely absent, hinting at the presence of an unnaturally hungry predator.
• Creatures born in this region are steeped in the energies of the nexus, they are more primal and wild than others of their kind. they might grow boney protrusions and coverings, spines, horns or other such defensive and offensive implements. Likewise all creatures in the valley are resistant to poison and are either poisonous, venomous, or both. Predatory creatures have heightened sense, are more resilient and harder to kill as their wounds heal at a greatly accelerated rate. 

If Caerosivous dies, the animals lose their supernatural link to them. The thickets remain but become wild and aggressive seeking to bring down and kill any creature that wanders too close until such time as there is a new guardian for the Nexus.