Combat

Combat in Terminal Descent is a turn-based system where ZERO uses loaded Programs and combat commands to fight Intrusion Countermeasures (IC) — hostile security programs that patrol The Lattice. Combat is one of several approaches to obstacles; players can also use stealth, hacking, or social skills to bypass encounters.

Core Mechanics

Turn Structure

Combat is turn-based. Each turn, the player selects a combat command, then all IC in the encounter act. Turn order is determined by speed:

Player selects action (ATTACK, DEFEND, EVADE, COUNTER, CLOAK, or use a program)
Action resolves
Each IC acts based on its behavior pattern
Status effects tick (buffs, debuffs, duration)
Turn counter increments

Damage Formula

Base Attack Power = program.damage + (combat_skill × 2) + deckMod

Defense Percent = min(0.80, defense / (defense + 50))

If attack ≥ defense:
  baseDamage = attack × (1 - defensePercent)
Else (attacker weaker):
  baseDamage = (attack² ) / (defense + 50)

Final Damage = baseDamage × effectiveness × critical × chain × mastery × variance(±10%)

Key design principles:

No zero damage — minimum 1 damage always applies
Defense is percentage-based, not flat subtraction
Stats grow linearly (Level 6 IC is roughly 3× stronger than Level 1, not 30×)
The 80% defense cap means 20% of damage always gets through

Critical Hits

Critical strikes deal 2.0× damage (2.5× with Precision Core upgrade).

Critical chance calculation:

Base: 10%
+ Analysis skill × 2% (max +12% at level 6)
+ Program Mastery Tier 5+: +2%
+ Program Mastery Tier 10: +5%
+ Operator Rank (per 50): +0.75%
+ Assault Frame Precision Core: +10%
+ TAUNT command: next ATTACK is guaranteed critical

Hard cap: 35%

Defense and Firewall

Defense Rating = (firewall × 5) + program.defense + deckMod

Cyberdeck firewall level directly impacts survivability:

FW 1 = 5 defense rating
FW 3 = 15 defense rating
FW 6 = 30 defense rating

Neural Damage (BlackICE specialty) bypasses normal defense:

neuralDmg = blackice.neuralDmg × (1 - player.firewall × 0.05)

Firewall reduces neural damage by 5% per level (max 30% at FW 6).

Combat Commands

Command	Effect	Notes
ATTACK	Deal damage using loaded offensive program	Primary damage action. Generates HEAT.
DEFEND	Reduce incoming damage this turn	Damage reduction based on defense rating. Sets up Mirror Protocol.
EVADE	Attempt to dodge all incoming attacks	Success based on speed + Stealth skill. Sets up Breach/Ghost Protocol.
COUNTER	Riposte the next attack received	Must be hit to trigger. Reflects portion of damage. Sets up Mirror/Siege Protocol.
CLOAK	Become invisible for several turns	Duration based on Stealth skill. IC cannot target you. Breaks on attack.
SPOOF	Fake credentials to confuse IC	Can cause IC to ignore you or attack allies. Social/Intrusion check.

Protocol Chains

Executing specific command sequences triggers powerful combo effects:

Chain	Sequence	Bonus
Breach Protocol	ATTACK → EVADE → ATTACK	+30% damage on final hit
Mirror Protocol	DEFEND → COUNTER → ATTACK	+50% damage, 100% counter reflect
Ghost Protocol	EVADE → CLOAK → ATTACK	+100% damage (2×), 0 HEAT generated
Siege Protocol	ATTACK → ATTACK → COUNTER	+25% damage to ALL IC in node

Secret Chains

⚠ SPOILER: Secret Protocol Chains [show/hide]

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Important: Chain multipliers stack with critical hits (e.g., Breach crit = 1.30 × 2.0 = 2.60×) but do NOT stack with each other.

IC Stat Growth

IC stats scale with level using a linear growth formula:

stat(level) = baseStat × (1 + (level - 1) × growthRate)

Stat	Growth Rate Per Level
HP	+20%
Attack	+15%
Defense	+12%
Speed	+8%
Evasion	+5%
Detection	+10%

This means a Level 5 Sentry has roughly 1.8× the stats of a Level 1 Sentry — challenging but not overwhelming.

Combat and HEAT

Combat actions affect HEAT:

Killing IC: +3 to +8 HEAT (varies by IC type)
Using aggressive programs: +1 to +3 HEAT
Ghost Protocol chain: 0 HEAT generated
Bypassing IC entirely (stealth/social): No HEAT gain
Mercy Protocol: Reduced HEAT vs. killing

Players pursuing the Ghost Protocol ending must keep HEAT ≤15 throughout Act III, making stealth and non-combat approaches essential.

Combat Strategy

Early Game

Focus on learning IC patterns through ANALYZE before engaging
EVADE is more reliable than DEFEND at low levels
Conserve programs — memory slots are limited

Mid Game

Protocol chains become essential for harder IC
Ghost Protocol (EVADE → CLOAK → ATTACK) is the most efficient chain: double damage, zero HEAT
Upgrade Cyberdeck processor and memory to load stronger programs

Late Game

BlackICE requires high firewall to survive neural damage
Hunter IC adapts to repeated strategies — vary your approach
Boss encounters have multiple phases; conserve resources