Cogmesh The Elder

 Steam Powered. Cogmesh is powered by steam, and thus, requires power. At the beginning of the encounter, roll 3d10 for his starting energy. if all dragons are slain, he only gains 2 power per turn. Taking cold damage negates 1 energy generation for a turn, and fire damage may cause overheating, dealing damage but adding 2 energy

Dragon Powered. Due to the amount of heat Cogmesh makes, red dragons have started living inside his metal casing and now power his body. For each living dragon inside Cogmesh's engine room, he gains 1 power per second. If a dragon dies inside of Cogmesh, roll a d4, and if the d4 lands on 1, the dragons body clogs up Cogmeshs cogs and takes his turn.

Speedy Cogs. Cogmesh may turn this ability activate and deactivate using his bonus action. While this ability is active, he can attack with legendary action as well as using 2 power per bonus action and regular action. When this ability in not active, he gains +2 armor and only consumes 1 power.

Energy Recovery mode. Doubles energy output at the cost of Cogmesh's turn. Cogmesh also looses all buffs. If Cogmesh has 0 energy, he is force to take this action on the current or next turn.

Energy Recovery mode. Doubles energy output at the cost of Cogmesh's turn

Action Weapon Attack. Punch +1 to hit, reach 75 ft., Hit: 18 (2d20+ 10) force damage. 

Action Melee Attack. Greatsword +1 to hit, reach 100 ft., Hit: 17 (4d20 + 20)  slashing damage. 

Action Ranged Attack. Pin Missile +2 to hit, range 50/300 ft., up to 3 targets. Hit: 18 (1d20 + 15) piercing damage.

Bonus Action. Speedy Cogs:  Cogmesh may activate or deactivate this ability.

Bonus Action. Energy Recovery mode: Cogmesh may activate or deactivate this ability.

N/A

Legendary Action Melee Attack. Quickened Greatsword +1 to hit, reach 100 ft., Hit: 15 (3d10+10)  slashing damage. 

Mythic Action. Self Destruct +10 to hit, reach 500 ft., Hit: 25(20d20+100)  Force/Magical damage.