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Monday, June 24, 2019

Mechs & Monstrosities TNT: Mechs

This is the second post for my Mechs & Monstrosities Hack for Tunnels & Trolls. The first post was solely for Massive Combat. This second post is about how to add mechs to your game! I generally prefer games to be as rules-light as possible, but there's just something really satisfying about customizing a mech, so I wanted to do something to make mechs a little more than just re-flavored PC types, so hopefully this is successful in that regard.

Escaflowne is a great fantasy mech anime

TNT Mech Mechanics

  • Treat mechs as Massive Creatures using M&M hack (link above)

  • Mechs have three scales 

  • PC mechs should probably all be at same scale, with higher or lower scales being for NPCs or have specific practical use-cases so that lower-scale mechs aren't strictly inferior to higher-scale mechs. Lower-scale mechs could be significantly cheaper, require fewer resources to build / repair / operate, or be able to maneuver in environments that larger scale mechs can't.

  • Monster / enemy mech stats are doubled per MR at massive scale 1 (as massive combat rules post), they're tripled for scale 2, and quadrupled for scale 3.

  • In combat between mechs of different scales, the mech with the higher scale gets advantage (always deals their Adds as minimum damage).

  • OPTIONAL RULES: If the mechs in the setting are supposed to be heavy or slow: 
    • Ranged attacks against a mech of the same scale always bypass opposed roll. 
    • Melee attacks against a mech of the same scale involve two SR rolls. Roll a strength SR to determine if PC damage bypasses the opposed roll, and speed SR to determine if NPC damage bypasses the opposed roll. Level of the SRs is the number of combat dice by MR (e.g. MR 0-9 = level 1 SR, 10-19 = level 2, etc.). Some mechs may count as higher level for the purpose of strength or speed SR. 
    • While these rules may slow down the rolls by requiring more SRs, it also speeds up the combat by increasing the amount of damage mechs take, reflecting the slow but devastating power of the mechs. It also potentially places greater emphasis on armor / damage reduction, which seems appropriate for mechs.

PC Mech Stats

  • Treat mechs as regular characters. Most stats can be conceptually mapped as-is. WIZ can just be the technomagical energy of the mech, IQ is the sophistication of the operating system or engineering necessary to contain certain advanced modules (i.e. spells). Mechs can be warriors, rogues, or wizards (or mystics), and a character's type does not need to align with their mech's type. All characters can apply a relevant talent bonus to SRs in their mechs, but otherwise mechs use their own stats, unless additionally noted below.

  • Warrior characters can add their own warrior damage dice to melee attacks with mechs, and also use their damage reduction ability with the mech. If the mech type is also warrior, triple rather than double the damage reduction. Warrior characters in wizard / rogue mechs can cast the mech's spells using the mech's WIZ.

  • Rogue and wizard characters can cast their own spells through their mech. Characters and mechs can each only cast spells that they know, with their own WIZ (i.e. a wizard's rogue mech can't use its WIZ to cast a spell that only the wizard knows).

  • Mech Gear Slots: two legs, two arms, two shoulders, head, back, and torso. These can affect terrain maneuverability, provide armor, add melee or ranged damage, or provide other special abilities. Arm and torso gears can be modeled after regular weapons and armor. Examples for other gear provided, but not an exclusive list.

  • In combat, a Dex SR can be made to do a gear attack, targeting specific gear slots, but unlike with ranged weapon Dex SRs, if the SR fails, the attack is a miss
    • If an NPC makes a gear attack (or PvP), if the attack is successful, the recipient must roll a luck SR to see if their gear takes wear (as regular wear and tear rules for armor), in addition to normal damage.
    • If PCs make a gear attack against an NPC, either the gear breaks automatically, or can take MR level hits (e.g. 0-9 MR can take 1 hit, 10-19 MR can take 2 hits, etc.)

Gear List

I'm terrible with logistics like cost, which is probably obvious given that I don't provide direct rules for mech cost (at least not yet). Having not tested any of this yet (>.<), I'd say let starting mechs take one arm and torso gear (weapon and armor respectively), and two additional gears of any kind. This gear list in general could probably use some work and is more of a proof-of-concept, but feel free to do your own thing with it.


  • These can be adaptations of regular weapons, shields, or gauntlets


  • These can be adaptations of armor


  • Light shoulder-mounted weapons: These are lighter-weight / lower damage weapons. 
  • Heavy shoulder-mounted weapons: These are heavier-weight / higher damage weapons.
    • Heavy weapons require both shoulder gear slots, even if only on one side.
  • Scout drone: A drone rides on their shoulder that can be deployed for reconnaissance.
  • Satellite apparatus: A radar dish or some other apparatus used to send signals to a satellite with some single purpose (reconnaissance, communication, orbital weaponry, etc.)


  • Jetpack: Short-range dashes, high or far jumps, dodging (+1 speed).
  • Wings: Medium to long-range gliding, if starting from sufficient altitude and acceleration.
  • Shell: Basically another shield slot.


  • Advanced Legs: Legs have the proportional strength and flexibility of real humanoid or animal legs (+1 speed).
  • Treads: Slower (-1 speed) and not amenable to difficult terrain (additional -2 speed on difficult terrain e.g. environmental factors, bumpy, etc.), but sturdier (+3 con) and can't be the target of gear attacks.
  • Wheels: Faster than legs (+2 speed) but suffer in difficult terrain (-1 speed) and are prone to going flat (minimum wear & tear SR level 2)


  1. Im really excited to see this when your all done. Mech battles would be awesome in TNT with all the different weapon types and such you can have. Very Cool!

    1. Thanks! If I had the time, or if someone else had the inclination, I'd like to test the core mechanics of Massive Combat and mech characters to make sure this is actually fun on a basic level, and then if it is I could build out a more robust set of Gears or pre-made mechs. Personally, I don't want it to be too crunchy, but I'd like it to be flexible enough that others could make it crunchier if they wanted to. TNT is pretty flexible in general, and I think the way damage works lends itself well to this or something like it, so as long as those core mechanics work the way I expect them to, I'll be happy.