MOBILE SUIT: TACTICAL BREACH
MASTER RULEBOOK // UNABRIDGED EDITION // V1.5
00 // INTRODUCTION: THE HELLAS EXODUS
Mobile Suit: Tactical Breach is a tabletop roleplaying game of asymmetrical warfare, tactical mecha combat, and desperate survival. You play as Exiles—rogue pilots, engineers, and Newtypes on the run from the Earth Federation's Man-Hunting Agency (MHA) inside the decaying slums of the Hellas colony cylinder.
Combat is split into two distinct phases: On-Foot Protocols (gritty, stealth-focused survival) and Mobile Suit Combat (high-octane mecha battles).
01 // THE CORE SYSTEM
The game runs on a unified d20 resolution mechanic. Roll 1d20 + the relevant Attribute against a Target DC or an Enemy's Defense (AC).
Core Attributes (Capped at 10)
- Reflexes (REF): Physical speed, dodging, stealth, and human-scale weaponry.
- Synchrony (SYN): Spatial awareness, MS accuracy, Newtype resonance, and Heat management.
- Technical (TEC): Hacking, repairs, and bypassing network endpoints.
- Composure (COM): Willpower, social stealth, and maintaining cover identities.
- Fortitude (FOR): Physical health, resisting toxins, and absorbing high-G impacts.
Derived Metrics
| Metric | Calculation |
|---|---|
| On-Foot HP | 20 + FOR |
| Max Heat Capacity | 10 + SYN |
| Total Defense (AC) | 10 + REF + Armor Bonus |
| Stability Save | 1d20 + FOR |
Cover & Line of Sight
- Light/Partial Cover: +2 to Defense (AC).
- Heavy/Full Cover: Breaks Line of Sight (LoS) entirely. Targets behind Heavy Cover cannot be directly fired upon unless specified.
02 // ARCHETYPES & ADVANCEMENT
Archetypes define your role and grant access to specific combat resources:
- The Ace Pilot: Uses Momentum to execute extra attacks or guaranteed critical strikes.
- The Newtype: Uses Insight Points to force re-rolls or predict enemy movements.
- The Engineer: Uses Experimental Payloads to build EMPs, flashbangs, or jammers.
- The Vanguard: Uses Command Points to grant allies movement or intercept damage.
Earn Evolution Points (EP) to upgrade Attributes (Max 10) or purchase Sub-Skills.
03 // THE XG-SERIES CHASSIS
Prototype frames built for asymmetrical warfare in colony environments.
XG-01 "BREACH" (Attack / Mobility)
XG-02 "AEGIS" (Defense / Heavy)
XG-03 "SIREN" (Support / E-War)
XG-00 "NOMAD" (Balanced / Prototype)
04 // ON-FOOT PROTOCOLS (HUMAN SCALE)
Grid Scale: 1 Square = 5 Feet. Turn Structure includes 1 Move (6 sq), 1 Action, and 1 Bonus Action.
Infantry Reactions & The Miracle Burn
- Dive for Cover: Spend Reaction (REF Save DC 14) to negate AoE/MS damage by moving behind Heavy Cover. You land Prone.
- The Miracle Burn: Permanently burn 1 Evolution Point (EP) to barely pass a failed lethal saving throw or survive fatal damage with 1 HP.
"Guns Are Loud" Rule
Firing non-silent weapons triggers a Stealth Check (1d20+REF vs DC 12). Failure increases the Campaign Alert Level. At Level 3, MHA deploys heavy units.
05 // MOBILE SUIT COMBAT (THE SCRAMBLE)
Grid Scale: 1 Square = 50 Feet.
The "Red Mist" Protocol
If a human-scale target is hit by a direct MS weapon and fails to Dive for Cover, they are instantly killed with no saving throw allowed.
Heat Management
- Shutdown: Exceeding Heat Capacity (10+SYN) drops Defense to 10 and loses the next turn.
- Emergency Vent (Full Action): Clears 6 Heat.
- Combat Vent (Bonus Action): Clears 3 Heat.
Maneuvers
- Stagger: Take 1/3 Max HP dmg = Stability Save (1d20+FOR). Fail = lose Reaction.
- Overclocking: Push reactor for +2 Move or +1d10 Dmg. Focus Roll (1d20+SYN vs DC 12). Fail = Permanent Malfunction.
- Called Shot: -4 penalty to target a limb/weapon to disable MS without killing the pilot.
06 // THE EXILE ECONOMY (DOWNTIME)
Reputation Tracks
- Exoneration (0-100): Below 30 = Terrorist status (-1 to Composure).
- Syndicate Rep: Access to black market parts and forged IDs.
- MHA Heat: High heat increases military scrutiny and Deadliness of ambushes.
Downtime Actions (Choose One)
Lay Low (COM): Reduce Alert/Heat | Scrounge (TEC): Repair Malfunctions | Train: Gain +1 Save bonus | Info Broker (SYN): Reveal Map data.
07 // ADVANCED SYSTEMS (OVERLAYS)
Reality-bending systems locked behind The Last Resort Protocol.
Activation: The Desperation Gate
Activate only if: MS is at 50% HP or less, or an allied MS has been reduced to 0 HP.
The Slag Tax
Deactivating an Overlay automatically causes 2 Permanent Malfunctions (roll 2d20 on Diagnostics Table).
08 // THE OVERLAY COMPENDIUM
OVERLAY 1: PSYCHO-FRAME (The Newtype)
- Mind-Machine Sync: Use SYN for Evasion and Initiative.
- Resonance Gauge: Replaces Heat ($15+SYN$). Overload = Paralyzed & permanent -1 COM.
- Remote Funnels: Resonance Check ($1d20+SYN$) to deploy up to 6 funnels dealing up to 3d10 damage.
- Structural Sympathy (Danger): Take >30 dmg = pilot takes 1d4 On-Foot dmg.
OVERLAY 2: LIMITER RELEASE (The Ace Pilot)
- Momentum Burn: Spend 3 Momentum; Momentum no longer resets on miss.
- Ghost Movement: Ignore Reactions and move through enemy squares.
- Chain-Strike: Kill enemy = refund 1 Action and 1 Bonus Action (1/turn).
- Meltdown: Every 1 point above Max Heat causes 5 Direct Damage to MS.
- Hemorrhage (Danger): Chain-Striking/Moving >6 sq = FOR Save (DC 14). Fail = 1d6 On-Foot dmg. HP 0 = Instant Death.
OVERLAY 3: COMMAND DATALINK (Engineer/Vanguard)
- Omni-Radar: Linked allies share LoS and ignore standard cover.
- Synchronized Fire: Paint target (Bonus Action); linked allies fire via Reaction.
- Sensor Ghosting: Force enemy MS within 20sq to COM Save. Fail = Jammed.
- Feedback (Danger): Ally takes Crit/Stagger = you are instantly Staggered. COM Save (DC 15) or lose 1 COM.