← Back to history
Leviathan BX-9 "Mawbreaker"Mech

Leviathan BX-9 "Mawbreaker"

legendary assault-class mech — 95 tons

Armor: 420

Heat Capacity: 48

Speed: 5

Jump Jets: No

Weapon Systems

Plasma Rail Cannon (right arm)6d12 plasma +10 heat
Ion-Charged Plasma Bolts (right arm (rail attachment))4d10 ion +8 heat
Plasma-Imbued Buzzsaw Sword (right arm (under-mount))5d8 slashing +5 heat
Heavy Laser Cannon (left arm)4d12 laser +9 heat
Twin Artillery Cannons (left arm (flanks))6d10 explosive +7 heat
Quad Missile Mortar (16 missiles, 8 warheads each) (back)8d10 explosive +6 heat
Dual Cryo Cannons (shoulders)3d8 cold +2 heat
Dual Miniguns (shoulders)4d6 kinetic +4 heat
Elbow Shuriken Launchers (elbows)3d10 slashing +2 heat
Sonic Screech / Tungsten-Shear Maw (head)5d10 thunder +6 heat

Special Systems

Fission Antimatter Core (Enhanced Power), Biovein Regeneration Network, Ion Field Amplifier (Rail Cannon), Targeting Computer MK-VII, Reinforced Pilot Cockpit (Upper Chest), CASE II (Ammunition Protection), Thermal Dissipation Fins (Cryo-linked)

On Hit: Ion Field Amplifier: When the Plasma Rail Cannon hits, the ion field doubles armor penetration. Ignore up to 15 points of the target's armor rating on that attack.
On Critical Hit: Warhead Cascade: On a critical hit with the Quad Missile Mortar, all 8 warheads in the struck missile detonate simultaneously. Deal an additional 6d10 explosive damage in a 20-foot radius.
Activated: Sonic Screech: Once per round as a bonus action, the Mawbreaker unleashes a sonic screech in a 60-foot cone. All ceramic and lightly armored targets (armor rating below 150) must make a DC 18 Constitution save or be Stunned for 1 round and take 5d10 sonic damage. Metal-armored targets take 3d6 burn damage.
Activated: Elbow Shuriken Mode Toggle: Switch between Launched (ranged 120 ft, 3d10 slashing) or Buzzsaw (melee reach 10 ft, 4d10 slashing + 2d6 ongoing bleed) as a free action on your turn.
Passive: Biovein Regeneration: At the start of each of the pilot's turns, the Leviathan recovers 15 armor rating points (up to its maximum) due to its living biomech structure.
Passive: Fission Antimatter Core: The Mawbreaker never runs out of power for standard systems. Weapon heatCapacity is increased by 10. If the core is breached (armor drops to 0), trigger the On Overheat effect immediately.
On Overheat: Antimatter Core Breach: If the mech exceeds its heat capacity or the core is breached, it detonates in a catastrophic antimatter explosion. All targets within 200 feet take 20d12 plasma/radiation damage (DC 22 Dexterity save for half). The mech is destroyed.
On Hit: Cryo Suppression: Targets hit by the Dual Cryo Cannons have their speed reduced by half and suffer -2 to attack rolls until the end of their next turn. On a critical hit, the target is Frozen solid for 1 round.

The Leviathan BX-9 Mawbreaker is a 95-ton assault-class biomech standing 70 feet tall. It is piloted from a reinforced cockpit housed in the upper chest, directly above its Fission Antimatter Core. The mech moves at Speed 5 and has no jump jets due to its massive bulk. Its glowing blue biotech veins power its Biovein Regeneration Network, restoring 15 armor rating at the start of each pilot turn. WEAPONS: Right arm mounts a Plasma Rail Cannon (6d12 plasma, ion-field armor pierce 15) with an under-mount Plasma-Imbued Sword usable in melee (5d8 slashing/plasma). Left arm carries a Heavy Laser Cannon (4d12 laser) flanked by Twin Artillery Cannons (6d10 explosive). Shoulders mount Dual Cryo Cannons (3d8 cryo, speed reduction on hit) and Dual Miniguns (4d6 ballistic). The back mortar fires 4 missiles per salvo from a 16-missile magazine (8 warheads each, 8d10 explosive, Warhead Cascade on crit). Elbows carry shuriken that toggle between ranged launch and buzzsaw melee mode. The head-mounted Sonic Screech (5d10 sonic) fires as a bonus action in a 60-ft cone and stuns targets with armor below 150. HEAT: Total heat generated per full salvo is capped at 48 (heatCapacity). The Thermal Dissipation Fins reduce heat by 4 at the end of each round while Cryo Cannons were fired this turn. SPECIAL RULES: The Fission Antimatter Core grants +10 effective heat capacity. If the mech is destroyed or exceeds heat capacity, the Core Breach detonation triggers (20d12 plasma/radiation, 200-ft radius, DC 22 Dex save for half). This mech counts as a boss-tier encounter for groups of 4-6 players at high tier.

assaultbiomechlegendaryheavy weaponsplasmarail gunartillerymissilessoniccryolasermeleeshurikenbossantimatterregenerationion fieldminigunmortarbiotech
Text: Claude Sonnet 4.6Image: Nano BananaStyle: Cyberpunk

“A 70 foot tall biomech with a mouth full of razor sharp teeth that can cut tungsten and release a sonic screech that can shatter ceramic and burn through metal. It has a fission antimatter core located in the top center of the chest. Right above that is the pilot's cockpit and then it has these somewhat bulky legs with a tail and it has these glowing blue veins all around it. On its left arm it has a laser cannon and two artillery cannons on the sides of that. On its right arm is a rail gun with a plasma imbued sword underneath it. The rail gun shoots plasma bolts that go through an ion field for maximized damage and then on the back it has a mortar that can launch four missiles at a time. The mech has 16 missiles each of which have eight warheads inside them to do a lot for maximum damage. On the shoulders it has two cryo cannons and two miniguns. On its elbows are two shurikens that can be launched or used as buzzsaws.”