MOBILE SUIT: TACTICAL BREACH

MASTER RULEBOOK // UNABRIDGED EDITION // V1.5 [cite: 3]

00 // INTRODUCTION: THE HELLAS EXODUS

Mobile Suit: Tactical Breach is a tabletop roleplaying game of asymmetrical warfare, tactical mecha combat, and desperate survival[cite: 8]. 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[cite: 9].

Combat is split into two distinct phases: On-Foot Protocols (gritty, stealth-focused survival) and Mobile Suit Combat (high-octane mecha battles)[cite: 10].

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)[cite: 12].

Core Attributes (Capped at 10) [cite: 13]

  • Reflexes (REF): Physical speed, dodging, stealth, and human-scale weaponry[cite: 14].
  • Synchrony (SYN): Spatial awareness, MS accuracy, Newtype resonance, and Heat management[cite: 15].
  • Technical (TEC): Hacking, repairs, and bypassing network endpoints[cite: 16].
  • Composure (COM): Willpower, social stealth, and maintaining cover identities[cite: 19].
  • Fortitude (FOR): Physical health, resisting toxins, and absorbing high-G impacts[cite: 20].

Derived Metrics [cite: 26, 27]

MetricCalculation
On-Foot HP20 + FOR [cite: 28]
Max Heat Capacity10 + SYN [cite: 29]
Total Defense (AC)10 + REF + Armor Bonus [cite: 30]
Stability Save1d20 + FOR [cite: 31]

Cover & Line of Sight [cite: 33]

  • Light/Partial Cover: +2 to Defense (AC)[cite: 35].
  • Heavy/Full Cover: Breaks Line of Sight (LoS) entirely[cite: 36]. Targets behind Heavy Cover cannot be directly fired upon unless specified[cite: 37].

02 // ARCHETYPES & ADVANCEMENT

Archetypes define your role and grant access to specific combat resources[cite: 39]:

  • The Ace Pilot: Uses Momentum to execute extra attacks or guaranteed critical strikes[cite: 40, 41].
  • The Newtype: Uses Insight Points to force re-rolls or predict enemy movements[cite: 42, 43].
  • The Engineer: Uses Experimental Payloads to build EMPs, flashbangs, or jammers[cite: 44, 45].
  • The Vanguard: Uses Command Points to grant allies movement or intercept damage[cite: 48, 49].

Earn Evolution Points (EP) to upgrade Attributes (Max 10) or purchase Sub-Skills[cite: 50, 51, 52].

03 // THE XG-SERIES CHASSIS

Prototype frames built for asymmetrical warfare in colony environments[cite: 53, 55].

XG-01 "BREACH" (Attack / Mobility) [cite: 57]

HP: 50 [cite: 59] | SPEED: 7 Squares [cite: 60]
[Hit & Run]: Reduce enemy to 0 HP or land a Called Shot to move 3 Squares as a Free Action. Does not trigger Reactions[cite: 61, 62].

XG-02 "AEGIS" (Defense / Heavy) [cite: 63]

HP: 70 [cite: 65] | SPEED: 4 Squares [cite: 66]
[Phalanx Frame]: Permanently counts as Heavy Cover for allies. Adjacent allies behind the Aegis break LoS[cite: 67, 68].

XG-03 "SIREN" (Support / E-War) [cite: 69]

HP: 40 [cite: 71] | SPEED: 6 Squares [cite: 72]
[Target Lock Data-Link]: Successful Combat Hacking grants Advantage to the next allied attack roll against that target[cite: 75, 76].

XG-00 "NOMAD" (Balanced / Prototype) [cite: 77]

HP: 55 [cite: 79] | SPEED: 5 Squares [cite: 80]
[Adaptive Reactor Cycle]: Once per encounter, use Emergency Vent (6 Heat) as a Bonus Action instead of a Full Action[cite: 81, 82].

04 // ON-FOOT PROTOCOLS (HUMAN SCALE)

Grid Scale: 1 Square = 5 Feet[cite: 86]. Turn Structure includes 1 Move (6 sq), 1 Action, and 1 Bonus Action[cite: 87].

Infantry Reactions & The Miracle Burn [cite: 88]

  • Dive for Cover: Spend Reaction (REF Save DC 14) to negate AoE/MS damage by moving behind Heavy Cover. You land Prone[cite: 90, 91].
  • The Miracle Burn: Permanently burn 1 Evolution Point (EP) to barely pass a failed lethal saving throw or survive fatal damage with 1 HP[cite: 92].

"Guns Are Loud" Rule [cite: 93]

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[cite: 97, 98].

05 // MOBILE SUIT COMBAT (THE SCRAMBLE)

Grid Scale: 1 Square = 50 Feet[cite: 108].

The "Red Mist" Protocol [cite: 107]

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[cite: 109, 110, 111].

Heat Management [cite: 112]

  • Shutdown: Exceeding Heat Capacity (10+SYN) drops Defense to 10 and loses the next turn[cite: 115, 116].
  • Emergency Vent (Full Action): Clears 6 Heat[cite: 117].
  • Combat Vent (Bonus Action): Clears 3 Heat[cite: 118].

Maneuvers [cite: 121]

  • Stagger: Take 1/3 Max HP dmg = Stability Save (1d20+FOR). Fail = lose Reaction[cite: 122, 123].
  • Overclocking: Push reactor for +2 Move or +1d10 Dmg. Focus Roll (1d20+SYN vs DC 12). Fail = Permanent Malfunction[cite: 124, 125].
  • Called Shot: -4 penalty to target a limb/weapon to disable MS without killing the pilot[cite: 126, 127].

06 // THE EXILE ECONOMY (DOWNTIME)

Reputation Tracks [cite: 131]

  • Exoneration (0-100): Below 30 = Terrorist status (-1 to Composure)[cite: 132].
  • Syndicate Rep: Access to black market parts and forged IDs[cite: 133].
  • MHA Heat: High heat increases military scrutiny and Deadliness of ambushes[cite: 134].

Downtime Actions (Choose One) [cite: 135]

Lay Low (COM): Reduce Alert/Heat | Scrounge (TEC): Repair Malfunctions | Train: Gain +1 Save bonus | Info Broker (SYN): Reveal Map data[cite: 136, 137, 138, 139].

07 // ADVANCED SYSTEMS (OVERLAYS)

Reality-bending systems locked behind The Last Resort Protocol[cite: 142, 143].

Activation: The Desperation Gate [cite: 144]

Activate only if: MS is at 50% HP or less, or an allied MS has been reduced to 0 HP[cite: 145, 146, 147].

The Slag Tax [cite: 148]

Deactivating an Overlay automatically causes 2 Permanent Malfunctions (roll 2d20 on Diagnostics Table)[cite: 149, 150].

08 // THE OVERLAY COMPENDIUM

OVERLAY 1: PSYCHO-FRAME (The Newtype) [cite: 153]

  • Mind-Machine Sync: Use SYN for Evasion and Initiative[cite: 154].
  • Resonance Gauge: Replaces Heat ($15+SYN$). Overload = Paralyzed & permanent -1 COM[cite: 155].
  • Remote Funnels: Resonance Check ($1d20+SYN$) to deploy up to 6 funnels dealing up to 3d10 damage[cite: 157, 158, 160, 161, 162].
  • Structural Sympathy (Danger): Take >30 dmg = pilot takes 1d4 On-Foot dmg[cite: 165].

OVERLAY 2: LIMITER RELEASE (The Ace Pilot) [cite: 166]

  • Momentum Burn: Spend 3 Momentum; Momentum no longer resets on miss[cite: 167].
  • Ghost Movement: Ignore Reactions and move through enemy squares[cite: 168].
  • Chain-Strike: Kill enemy = refund 1 Action and 1 Bonus Action (1/turn)[cite: 169, 170].
  • Meltdown: Every 1 point above Max Heat causes 5 Direct Damage to MS[cite: 171].
  • Hemorrhage (Danger): Chain-Striking/Moving >6 sq = FOR Save (DC 14). Fail = 1d6 On-Foot dmg. HP 0 = Instant Death[cite: 172, 173].

OVERLAY 3: COMMAND DATALINK (Engineer/Vanguard) [cite: 174]

  • Omni-Radar: Linked allies share LoS and ignore standard cover[cite: 175].
  • Synchronized Fire: Paint target (Bonus Action); linked allies fire via Reaction[cite: 176, 177].
  • Sensor Ghosting: Force enemy MS within 20sq to COM Save. Fail = Jammed[cite: 178, 179].
  • Feedback (Danger): Ally takes Crit/Stagger = you are instantly Staggered. COM Save (DC 15) or lose 1 COM[cite: 180, 181].