Steadfast5e - Exploding Damage is a lightweight, high-fidelity Fantasy Grounds Unity extension that brings the classic exploding dice house rule to all damage rolls in D&D 5E (both 2014 Legacy and 2024 rulesets). It turns every weapon attack and spell/power damage roll into a dynamic, swingy experience that rewards high rolls and creates those memorable "holy crap" combat moments common in OSR and gritty low-fantasy games.

Core Feature

When any damage die rolls its maximum possible value (e.g., a 6 on a d6, 8 on a d8, 4 on a d4), it automatically rerolls and adds the new result to the total. This chains indefinitely—if the reroll is also a max, it explodes again. This applies universally to:

• All weapon damage (melee, ranged, PC, and NPC/monsters)
• All spell and power damage (fireballs, magic missiles, cantrips, etc.)
• Any standard damage clause in the 5E action system

Normal rolls remain completely unchanged until a die actually explodes. No extra dice are pre-rolled; the explosion only triggers on max results.

Technical Implementation (Clean & Respectful)

This extension does not reinvent the wheel or add heavy custom logic. It intelligently leverages FGU/CoreRPG’s native compound-explode die mode ("e!" or bExplodeCompound flag)—the exact same engine feature used by Vorpal weapons (in legacy contexts) and Shadowdark’s Momentum mechanic.

The implementation is elegant and minimal:

• It monkey-patches the single central entry point ActionDamageD20.getRoll(rActor, rAction).
• Before delegating to the original function, it walks every damage clause in rAction.clauses and sets bExplodeCompound = true.
• FGU’s built-in dice builder (DiceRollManager.addDamageDice) handles all the actual rolling, rerolling, and chaining.
• One patch covers everything: PC weapons, NPC actions, spell damage actions, etc.

This approach ensures rock-solid compatibility, minimal performance impact, and future-proofing. No stock ruleset files are modified.

Known Limitation (Transparent)

On critical hits, the original damage dice still explode normally. However, the extra dice added by 5E’s standard critical doubling rule (handled in ActionDamageD20.applyModCriticalDoubleDice) do not inherit the explode flag. This is a limitation in the core ruleset, not the extension. In most play, it rarely matters, but it’s documented for completeness.

Part of the Steadfast5e Suite

This extension is designed to work seamlessly alongside the rest of the Steadfast5e collection for grittier, more grounded, OSR-inspired 5E play:

• Expanded Skills
• HP Debloat
• Proficiency Bonus Cap (+4 max)
• Gritty Realism Rest (coming)
• Location System (coming)

Together they create a cohesive low-to-mid fantasy experience with meaningful attrition, tactical depth, and swingy combat without overhauling the entire system.

Ideal For

• OSR / old-school enthusiasts running 5E
• Tables wanting deadlier, more exciting damage rolls
• GMs who love the “exploding dice” feel from Savage Worlds, Shadowdark, or classic D&D house rules
• Players who enjoy those rare but epic damage spikes