Warforged Iron Warden

Siege Engine. Iron Warden's shake the earth with every step, and are able to destroy small buildings with ease. Deals triple damage to buildings and structures.

Immutable Form. The Iron Warden is immune to any spell or effect that would alter its form.

Magic Resistance. The Iron Warden has advantage on saving throws against spells and other magical effects.

Extradimensional Interference: Affected creatures can't move or travel using teleportation or by extradimensional or interplanar means.

Multi-attack. The Iron Warden makes three punch attacks, or one shot with it's Armageddon Proton Cannon.

Punch. Melee Weapon Attack: +8 to hit, reach 20 ft., 1 target. Hit: 15 (2d10 + 5) Bludgeoning damage. 

Armageddon Proton Cannon. RangedWeapon Attack: +10 to hit, range 50/500 ft., 1 target. Hit: 20 (3d10 + 10) Fire damage.

Mechanical Failure. When this creature is hit with 60 damage or more from a single attack, roll a d6 to inflict a random failure on it.

1: The Warden's leg rotors lock up, preventing movement in it's next turn.

2: The Warden's primary targeting system malfunctions, gaining a disadvantage to it's next ranged attack.

3. The Warden's back up fuel cell ignites, dealing an additional 1d10 acid damage each turn for 3 turns.

4. The Warden's alarm blares, deafening any creature within a 150 ft radius.

5. The Warden's arm piston seizes up, making the next melee attack do two hits instead of three.

6. The Warden's Proton Cannon jams, preventing the next ranged attack from hitting the target.

Each Warden has 3 Reinforcement points. The Warden may use these points at any time to call in additional Warforged troops to aid it in the fight. 

Warforged Battalion (Costs 1 Action). A drop pod is shot from The Mithril Forge to the Warden's current location in a 100 ft radius. This pod contains one battalion of Corrupted Warforged.