How to create mechs in Dungeons and Dragons.
Note that I'm not a huge fan of mechs, but I got to thinking about how a mecha game with Touhous would run, so here I am. Also note that these rules are not going to be totally balanced; unfortunately, demand for mech games is low in my playgroup, so I can't really test it. This is also just a bit of a side project, so I'm not really wanting to put too much thought into it. However, the rules should be functional. Think of it as giving your players magical items; they're not balanced, so you, the DM, have to work out what to give people.
Mecha Equipment
Mecha Weapons
Power Sources
Bodies
Pilot Interface
Damage Control
Add-ons
Mechas follow similar rules for functioning as a normal character.
Mechs have their own Strength, Dexterity and Constitution scores.
Strength is dependent on the machinery that powers the mech.
Dexterity is based on the control interface, and is limited by the pilot’s Dexterity.
Constitution is based on damage control systems.
Intelligence, Wisdom and Charisma are dependent on the pilot.
Weaponry
Mechs are equipped with their own weapons.
Projectile weapons, such as cannons, machine guns and missiles, use ammo, and have low heat, making them useful for a well-supplied force.
Beam weapons, such as lasers, have unlimited ammo, but require lots of heat, making them more useful for a battle of attrition.
Weapons can either be mounted on hardpoints, or held, if the mech has hands.
Handheld weapons are typically easier to aim and easily interchangable, but require sophisticated interfaces that allow the pilot to use their hands.
Hardpoint weapons are less accurate and require substantial remodeling to change, but are easier to produce, more can be mounted on a single mech, and the largest of weapons can only be mounted this way.
Durability
Each part of a mech has its own AC and HP. When a part is reduced to 0 HP, it is destroyed, and must be replaced. A more cinematic game might only require it to be repaired instead.
If the torso section is reduced to 0 HP, the mech is destroyed.
Energy
A mech has an energy rating. This determines how much equipment it can operate. It is dependent on the mech’s power source.
Heat
Mechs also have a heat rating. This determines how much a mech can do in a single turn. It is dependent on the mech’s heat sinks. Heat lasts until the beginning of the user's next turn. If a creature has multiple turns, it lasts until the beginning of the corresponding turn from which it was generated.
John has a heat rating of 3, and is equipped with a cannon that generates 1 heat when fired, and a laser that generates 3 when fired. If he fires his laser, he will generate 3 heat, preventing him from firing his cannon as well. If he fires his cannon instead, he will only generate 1 heat. Since he still only has a limit of 3, he can't fire his laser as well.
If John has a laser missile defense system that generates 2 heat when used, he might opt to use the cannon over the laser. He generates 1 heat by firing the cannon, and can still generate 2 more heat before reaching his limit of 3. An enemy attacks him with a missile later that round; he can still use his laser missile defense system to shoot it down. If he had fired his laser, he would not have been able to use the laser missile defense system, because he would have been at his limit of 3 heat.