Alatreon

Elder Dragon constitution. This creature is immune to exhaustion, and is unaffected by traps, and meat (bait), but vulnerable to paralysis and sleep.

Airborne. While the Alatreon is in the air it is immune to lightning damage

Weak points. The Alatreon has three weak points (Head, Wings, Tail), each of which can be broken (roll a d100, if > 65 that part is broken). If the horns are broken, damage is reduced by half for 3 turns.

Multiattack. The Alatreon can make 4 attacks 2-4 of which can be replaced by the legendary action

Bite. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 17 (2d10 +7) [piercing] damage.

Claw. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 13 (2d6 +7) [slashing] damage.

Tail. Melee Weapon Attack: +10 to hit, reach 20ft., all targets within range. Hit: 15 (2d8 + 6) [bludgeoning] damage.

Gale force. Ranged Weapon Attack: +10 to hit, range 30 ft., all targets within range are knocked prone CON Save DC 20. Hit: 5 (2d4 + 5) [Force] damage. 

 Elemental Attacks. Ranged weapon Attack: +10 to hit, range 150ft/20ft sphere., use one of the attacks listed below, recharges every 3 turns

Flame Breath. causes target make a DC 20 DEX save, upon failure target. Hit: 10 (2d6 + 3) [Fire] damage.

Ice spray. causes target to make a DC 20 Dex save, upon failure ice forms around the targets body slowing their movement speed by 10ft. Hit: 10(2d8 + 3) [Cold] damage.

Summon Lightning. Target must make a DC 20 CON save. Upon failure target is paralyzed for a turn. Hit: 1 (11d8 + 3) [Lightning] damage.

Oil spray. Target must make a DC 20 Dex save. Upon failure target is covered in an ignitable liquid. Hit: 5 (3d6 + 3) [Water] damage.

Flight. Using a bonus action, the Alatreon can flap take flight or land. Flash bombs can be used to stun the creature for one turn causing it to fall to the ground prone.

Opportunity Attack. The Alatreon can make an Opportunity Attack when a target leaves its range using its action, its Bonus Action, its Reaction, Or one of its speeds. To make the Opportunity Attack, take a Reaction to make one melee attack with a weapon or unarmed Strike against the provoking creature. The attack occurs right before the creature leaves its reach.

Mode Change (2 Actions): The Alatreon has 3 modes which it can switch between using its legendary action.

Fire Active: The Alatreon is it is immune to the Fire element, resistant to Lightning and Radiant elements, moderately weak to Water, and weak to Ice.

Ice Active:  The Alatreon is immune to the Ice element, resistant to Water and Radiant elements, moderately weak to Lightning, and weak to Fire.

Dragon Active: In this mode mode, the Alatreon has no immunities but is resistant to Fire, Ice, Lightning, and Water elements, with only a moderate weakness to the Radiant element.

Charge (2 actions): The Alatreon is able to muster its power and energy in its horns. At that moment, the horns will be surrounded by little sparkles. After 3 turns, it will absorb those sparkles and turn blue, before hovering around the area and starting a thunder and icy rampage for 4 turns. If Horns are broken (the action is halted, and or prevented (permanently) from taking place) 

If the legendary action Charge is completed the Alatreon can use the options below as a legendary action. 

Rampage (Costs 3 Actions): While rampaging, all attacks deal an additional 10 damage. If airborne while rampaging, take half damage lasts 4 turns

Escanton Judgement (Costs 4 actions): All targets within 120ft must make a DC 20 survival check, upon failure, this attack releases all of the energy Alatreon has stored and releases it as a destructive wave of elemental energy, 1(5d10) [Fire] damage, 1(5d10) [Lightning] damage, 1(5d10) [Cold] damage, 1(5d10) [Water damage], 1(5d10) [Radiant] damage. This attack can only be used once every hour.