D100 RPG Compatability And Conversions

I am literally sitting in front of my embarassingly big collection of RPG books. Embarassing because it is three 180cm long shelves left after another big clear out!

The good news for me though, is the content is much more streamlined and therefore more likely to be used. If a friend asked to play a game in a period, theme or even specific sub-genre, I am probably able to handle it without resorting to a non d100 system. Anthopomorphic animal characters? Pirates with supernatural themes? Zombie Apocolypse or Vampire plagues? Giant mechs? Maybe just some simple historical hack and slash? All good, all at hand.

But what if one of my rare survivors from the greater collection appeals and I want to run it as a d100 game because it is (a) more familiar to me and likely my players or (b) it is just better/easier/more coherent and flexible?

Lets look at what is on the shelf.

The Mouse Guard

One of the primary draws are hit locations, which makes big vs small creature fights possible.

Yes I can do anthropomorphic animals (Historia Rodentia, Teenage Mutant Ninja Turtles or generic), but the charm of The Mouse Guard is a strong draw. The support materiel, which is the bulk of my complete collection is a fine place to start. Stories are stories and the power level and theming are perfect for a d100 style game (no-magic, low power, classic medieval, just mice).

Mythras Imperative fits, as does Legend or the BGB. Systemically, you are replacing “Wises” with skills and mentors with, well mentors and family background and The Guard with an organisation. These things can act as a guide, as they would in any game. I feel that even without the RPG’s (1 & 2e), just the comics would suffice for background.

Hit location based combat systems fill in the missing link, that is, how does a little mouse kill a giant beast without getting squashed? There are rules at hand for size differences, but something as simple as tiny creatures attack the location they are near means the little mice only have to maneoeuvre to the right place to hit where they need. Big creatures in turn, have a penaty to hit little targets (or little creatures can Dodge, big ones cannot), again already an option in some systems.

The One Ring

TOR is another system primed for conversion. The power level is again low and realistic and magic is in the world but no more prevalent for most than Mouse Guard. Characters are simply a matter of creating skill lists for each culture and handling “madness” or taint is right in the wheel house of CoC’s sanity rules (but the ones in TOR can basically work also). The dice mechanic is unique, but lines up quite well with a d100 game, even the fatigued rule can simply be an added level of difficulty (or reversing the dice?).

Monsters in TOR cannot be taken lightly, which is the same as any d100 game, but proabably a non-hit location combat style would be fine, like maybe Openquest or Magic World?

Both LOTR games offer the same background and attempt to align themselves to each other, so get one right and you have both covered

Adventures In Middle Earth (5e)

AIME is the 5e conversion of above, so the same applies, mostly. This is TWORPG* heavily restrained, so no real issues. The “softness” of a hit point pool and levels based game is replaced by the more realistic paradigm of a d100 system which can really only be good. The release from levels and classes gives a freedom that I always prefer and the source material is roughly identical to TOR, so either-or. Balancing encounters and rewards is actually not that hard, because in d100 games, everything is potentially a tough hurdle.

Of course, there is the now long defunct MERP/Rolemaster d100 system, still available in PDF.

Iron Heroes (3e)

This is a TWOPRG heart breaker, pushing things into the more heroic end of the hobby, so it is a tougher fit. Or is it? The gritty feel of Iron Heroes has always felt like a d100 game near miss. The inflated hit point totals can be mimicked by a base line of more hits and higher skills (Astounding Adventures has some good pulp ideas). The Heroes could have Siz+Con for hits (supporting cast x1/2) and with skills in the 70%+ range, they will be hard to best, but never impossible.

These two have much in common. Classic Fantasy is designed to simulate OST levels based games, so drop the magic and it can be very close. The basic flexibility of Mythras, Legend, Magic World or Openquest though fit even better. I would even say much better as the core of Iron Heroes is limited to re-imagining the Fighter and Rogue classes, something d100 skills based games do so very well without limits.

DC Adventures, Marvel Heroes, Champions etc.

A supers game about the DC universe using a d20 system or Marvel with a dice pool system. These are generally right in the Destined or Superworld wheel house, especially the Batman or Spiderman level. Using these as a guide (the reason I held onto them), it is a hobby in itself to regenerate these whole universes in Destined (for personal use only of course). Super World is an option, but Destined is the “new shiny”.

Most Supers games end up at the same place after travelling different roads. I have only skimmed Destined, but between it and Superworld, I have a few ways of travelling that road.

The Witcher

Very few game systems could do The Witcher justice as well as the origional game has. The lethality, depth of detail and gritty realism is very similar to Deus Vult, but any d100 game could handle it. Mythras/Legend in particular are good examples of strong and detailed one-on-one combat systems with enough crunch to feel right. The Witcher series or the RPG can provide all the necessary monster weaknesses and tricks, so converting is pretty straight forward. I feel there is even more room for creativity within the world provided using a d100 base using all the resources available, because most Witcher creatures are based on fairytale precedents.

Using a d100 game would allow the GM and players to replace some of the detail TWRPG is known for, with more open role playing. Many of the things the game forces on players are base requirements, just called out specifically, so it is really just up to the GM to set the level of detail and tone, such as equipment maintenance, daily expenses. All RPG’s go at a pace and with details set by the GM and to a lesser extent the players. Race into fights with superior enemies, worn or untried equipment, fail to learn lessons or do your home work and reap what you sew.

Games that feel the need to force extra processes and details on their players are fine if they hit the right chord, especially if they are simulating a specific flavour, but they can feel rail-roady if not. TOR, Mouse Guard and TWRPG can all feel a little “mechanically inflexible” , but the background and feel they provide are excellent to mine for information. One of the reasons I prefer AIME to TOR for example, is the slightly less controlling nature of the 5e converted game.

Zweihander, a new game, still on its way here, but a known commodity, would make a great Witcher adjacent game. If anything it is even darker and more violent.

Immersive, crunchy and lethal monster hunting with everything at stake.

Savage Worlds

For a long time, I wanted to use SW as my lite “pulpy” system, and d100’s for more realistic stories, to the extent that I was “mirroring” genres between them, an idea that does not seem to be just mine. Some games like Modiphius’s Achtung Cthulhu, even come as a CoC/SW cross-over system.

SW really fell out of favour with me during it’s latest edition update. I do still have the SWADE book, but probably not for long. If the SW Supers and Sci-fi expansions come out soon, there is a slim chance i will go back down this road, but probably not, considering my current direction. To be honest I never felt totally comfortable with the game, but grew it sometimes reluctanlty as my counter point to others. I even tried to slot it into my Malifaux rework, but again it just defied me.

Savage Worlds sells itself as the ultimate on-the-go RPG, but to be honest, I find d100 games even quicker. Explaining % mechanics comes pretty much immediately. Explaining “raises”, multiple die types, “wild” dice, card driven initiative and “Bennies” and when to use them can be less straight forward. The whole system is actually a collection of sub-systems.

Generally the only complaint d100 games generate are its relatively lethal (i.e. realistic) combat, which siimply makes players adapt their expectations and live a little in fear (all good), and a reputation amongst experienced gamers of being “swingy”, which is partly shared illusion and easily enough mitigated. It is not as swingy as SW though.

Tellingly, new RPG players rarely find either of these two things odd or hard to digest. Only players coming from other games get caught out.

13th Age

This one is tricky. I have 13A as basically my anti-d100 release valve. Converting it seems odd and ironic, as one of the few d100 games I have chosen not to explore is the new Runequest, the original d100 game. I feel the 13A version fits better for me! If I had to do the 13A world, it would use a simple system, probably Openquest with many of the same concepts used. I would expect to go through more characters though. The “One Unique Thing” and Icon relationship rules can be ported over wihout issue.

Again Classic gets another image share, because of levels etc, but Openquest would be cleaner and more “magical” and it has Ducks (for Runequest).

Warhammer 4e

Why swap out one d100 system for another d100 system? The source materiel is massive and engrossing and the feel second to none. The system however is dense and inconsistent. It often occurs to me, that all that stuff could be so easily handled by a more flexible and fluid d100 system, especially the convoluted dice mechanics. Re-making all the careers in d100 terms would be easy and fun and the power levels are similar. The reality is, games like WHFRP use constraints to focus character development and creation, that good old fashioned role playing can fill.

There is also Zweihander of course, which is an actual WHFRG replacement game.

I just ordered Zweihander, so this is probably a rendundant conversion, but easy enough done. Magic World does have Beastmen as does Openquest.

Monsters and Other Childish Things

An odd but cool little game that escaped the recent cull thanks to it’s theme and cool art. There are several d100 systems that could handle something like this. It could simply be the story of the early days of a super hero, as could have a conversion of Better Angels (a game where the player next to you plays your possessing demon and on around the table), a game from the same series I gifted recently.

The monster as alter-ego/companion/possessor/frenemy is a common theme in pop culture (ET, Will Robinson from Lost In Space to Venom as examples), so most supers or super natural systems can fit this in seemlessly. The games extra books add the inspiration, but systemically, nothing is hard to re-hash. MAOCT actally uses a pool of D10’s system. The red and blue dice I bought for it have been pressed into service for my d100 games, so conversion seems natural.

After The Vampire Wars, Destined, the BGB, Mythras Imperative, Bare Bones (any). So many options.

Mongoose Traveller 1 & 2e

This is too easy. M-Space is a clone of the original Traveller, which is exactly what the two Mongoose Traveller editions are. M-Space is less tied to a back story, is cleaner and more versatile and can be crossed over with any other Mythras style game or mechanic. I feel it is a better option all up. I also like the moody and minimalist art more (Trav 2e art leaves me cold). If I want a more pulpy game, Frontier Space is at hand as is the BGB.

There is even a “Pirates of Drinax” Traveller to M-Space conversion document available.

Percentage systems can feel a little mathematically heartless some times, something like the hand of the “cold hard universe” feel in hard sci-fi.

Hero System

One of the great RPG rivalries of the 80’s through to the early 2000’s was the one between the generic Hero/Champions system and BRP. Both are able to incorporate most concepts and styles and both are stable. It is interesting to note, they are both also roll under systems, one using d100, one d6’s.

My preference is for BRP for most “grounded”, fantasy or historical games, Hero for more contemporary and supers styles, but I do find hero a bit dry and mathy and even though it plays easily, character development is usually a full evening on its own and big fights can also hog a full session. With a BRP game, you can pretty much design a character, explain the basic processes (% roll under), whip up a scenario and play it with new players in the same evening. Many of my early CoC games had debutant players who generally slotted in seamlessly. Even early casualties could be replaced quickly enough.

Hero provides mathematical balance in the extreme, BRP supplies more character, with simplicity. This is less of a conversion than a choice, but even a Hero specific story can usually be converted in concept. Something that helps me pick d100 is the collection of games I own now. The latest Mythras and earlier BRP genre books cover so many bespoke story themes, I often have enough to work without going fully generic, which is always easier.

Over six editions, Hero has managed to leave huge back catalogues of resources out in the cold (4e in particular). D100 systems never seem to abandon older product entirely.

*The Worlds Oldest Role Playing Game (just).