Has any game cracked a "2 or more player characters temporarily fuse into one character" gimmick that is actually fun/interesting/etc.?
A lot of popular media (off the top of my head - Dragonball Z, Transformers, Steven Universe, Bionicle) includes scenes where two or more characters combine together into a single, more powerful character.
In an RPG, this presents a couple big design issues:
- you need to adjudicate how players make decisions for their combined form, and make that as enjoyable as two players getting to speak for their characters individually
- you need a set of mechanics that navigates the space between overpowered (combined forms are always so overwhelmingly superior that you would always choose to combine) and underpowered (the perks don't outweigh the loss of action economy and it's never a good idea to combine) to make it an actually interesting decision.
In short, this is a trope that is fun to watch on a screen, and figures into popular media, but it's hard for me to see it coming to life on a tabletop. **I'm looking to be proven wrong - tell me about the games that actually make this work.**
**Example of an attempt at this mechanic:**
I have the Renegade Transformers RPG "Enigma of Combination" splatbook that includes rules for this which are detailed, but I've never actually seen them in play and don't have an abundant trust that they will fulfill the above criteria. They at least clear the hurdle of being fun to think about in character creation.
- characters take an option at creation or as a level-up perk to become part of a combiner. As part of taking these options, they get a choice of what specific bonus benefit they provide to the combined form (e.g., better defenses, speed, a pair of skills, a weapon slot, etc.)
- to combine, all characters must be near each other, spend a character resource (energon points) and an action.
- combiners are one or two size categories larger than their components, have the highest of each stat and skill* (it's slightly more complicated) among the components, certain class features, the slowest movement among the components, and a few other fiddly bits.
- Attacks are based on a single component's best attack, with damage doubled or tripled. Characters in a combined form still take damage as individuals, divided equally from damage taken by the combiner unless an attacker makes a called shot at a penalty. When more than half of the components are at 0 health, the combiner breaks apart unless another energon point is spent.
- the game does not prescribe one method for decision-making in the combined form. "If a combiner's form is made up of a single PC and an assortment of NPCs, the player character is obviously in charge of the Combiner form's actions. In the cases where multiple PCs make up a Combiner form, the players might either decide what the Combiner form does by consensus or trade off control over the Combiner form from one round to the next."