Converting Characters, Powers, etc. from one gaming fantasy world in to another is not usually too difficult because most stats in most games are fairly similar on some level. Usually there is a roll done to check if some action is successful or not. If it is successful, there sometimes is another roll to determine what actually happens, or how successful the success was. The different gaming systems have different ways of doing that – some use D20s, some use D10s, some use D6s, and some actions, especially those that are skill based instead of against a particular player character or non-player character, are based on on a percentage, usually determined by two D10s are rolled, and one counts as the 10s part of the % and the other counts as the ones part of the %. A roll of 9 and 9 would be 99%. A roll of 0 and one would be 1% unless the one was in the tens slot, in which case it would be a 10%. On skill checks like that, the Game Master, or some pre-planned skill check base is used to determine if the roll is over the amount needed to successfully do whatever it is that the character is trying to do.
Since everything in all gaming systems is based on a check for success of failure, it’s usually just a matter of comparing the two systems you are trying to convert to or from against one another to see in what way you can play with the numbers to get to the average and go from there in all conversions.
For instance, World of Darkness games are usually based on dots that make up attributes or skills. 5 dots is usually considered about the highest humanly possible attribute. 10 dots is considered about as powerful as god in whatever skill that it is that those points are in. In that system, each dot represents a 10 sided dice that is rolled to check against some number, usually determined by the books or the game master – oops, I mean “story teller.”
In other books like Palladiumbooks Rifts, Hereoes Unlimited, etc. Most non-combat actions are based on skill checks that are % based, and most combat actions are based on the roll of a D20 to determine if a hit, punch, or power that is used successfully hits. That is sometimes contested by another characters roll of a D20 for defensive actions such as parrying, dodging, etc. If no defensive moves are used, the attackers D20 roll is usually contested against the other character’s armor, which has an armor rating… Rolls above the armor’s rating does damage to the character inside of the armor. Rolls below that do damage to the armor itself, unless the armor is a special armor such as a mutant’s metal power that gives them a high armor rating, in which case a roll below the armor rating usually does no damage. A roll of a “natural 20” or 90% or more is typically a super success, usually doing twice as much damage, or making the successful check against a skill super successful. For instance, you checked against your lockpick skill to open a bank vault – a roll of 95% when you just needed a 70% might mean you got in, no alarms went off, and there is actually the keys to a lamberghini parked outside that has no alarm system sitting on the floor of the vault. A roll of 1 or 2% is usually a miserable failure – so in the same situation, that would result in a full swat team showing up, the alarm going off, and you broke your lockpick and got your fingerprints all over the place.
I have played both of those game systems and loved them and successfully integrated them by simply thinking about how the dot system works vs the % system and the D20 system. Different people doing different conversions might come up with other conversions, but what I typically came up with was that 5 dots = 99% or so, so each dot = about 20% for skill checks… and on average, one dot = +3 in d20 rolls, giving 5 dots +15 advantage on all d20 rolls, which is really just about the best most powers and things can give you in the Palliadium world.
Now go put all those vampires, werewolves, mummies, wraiths, and things in to your Rifts or Heroes Unlimited Campaign to add a whole bunch of new layers of complexity to the world… or go the other way and put some of those nearly unkillable vampires from Heroes Unlimited up against the Camarilla of Chicago or the Sabbat of New York City, etc. Perhaps a new vampire hunter is an invulnerable mutant with supersonic speed. Maybe a demigod from Rifts World Books have found a rift in to the World of Darkness and have decided to take on the eternal mummies or maybe even Caine and Lilith one on one. There’s literally unlimited potential to bring your heroes unlimited opportunities for role playing.
In a future post I might put in some rules about converting to and from other game systems.