The following House Rules have been used in the SisterWorlds when playing Advanced Dungons and Dragons.

G1. Stats are rolled using the 2d6+6 method, ensuring campaign quality characters. The average stat is around thirteen, and the lowest possible stat is an eight. Seventeens and eighteens are a bit more common with this method, but such high stats in a few areas will be needed to survive in the Sister Worlds.

G2. All characters begin with maximum hit points at first level. It makes no sense to have a character with thirteen stats for the average, and yet a bad die roll leaves him with a one or a two for hit points. The minimum damage from any weapon could very nearly kill a character with such low hit points – and a game ending so quickly for a player is not exactly a well remembered one.

G3. On Gaeleth, there are only four primary races to choose from. The kender, the halfling, and the gnome have been wiped out. In addition to the humans, all that remains are the dwarves and the elves, and a new race, the tomanths. Most of the various subraces are available, providing for a wide variety of backgrounds and characters. For the more experienced roll player, there are also orcs and ogres. Other races are subject to the DM's scowl, and require considerable smooth-talking. Gnomes are available on Brijanis, and halflings and kender are available on Jazed. Also, the subraces are not as per the handbooks; see attached for more information.

G4. Humans may be multiclassed characters, and kits are allowed to all classes. Humans, of all races, can adapt to nearly any situation; they have the greatest range of character, both mentally and physically. Multiclass capabilities must be compatible, and varied – no human could be a paladin-assassin or a druid-cleric. In the instances that abilities for the two classes overlap, such as in ranger-thieves, the better attribute is taken; the abilities are not cumulative.

G5. There are no psionicists on Gaeleth, and there are no wizards on Jazed. There is a 33% chance that a character might be a psionicist on Jazed, and a 3% chance on Brijanis. A natural roll of 100% on any of the three worlds indicates that the character is a 'null' (see the Jazed reference on psionics). 'The Risks' of rolling, from The Complete Psionics Handbook, do not apply to the rolls. The gods of Jazed suck up magical energy like siphons, and powerful sources of magic are quickly hunted down by the underlings of the gods, feeding off of artifacts and the souls of magic-users. Psionicists on Gaeleth were hunted down to extinction millennia ago, after the Sister Worlds War, and the gene was wiped out of the population.

G6. PCs are not allowed to choose Neutral Evil or Chaotic Evil as their alignments. Anti-player characters will not be tolerated, and these alignments cannot be anything but. All other alignments are allowed, although Chaotic Neutral characters will be monitored extermely closely. Players all too often think that by choosing Chaotic Neutral as an alignment, they can just do whatever the hell they want.

G7. Gaeleth and Jazed have a limited selection of gods and goddesses from which to choose character faiths; Brijanis has the full range of deities to choose from, so long as they are not from either Gaeleth or Jazed. Characters on Gaeleth are highly encouraged to select a deity; if one of the deities currently available is not to a characters liking, then the DM can always create a god.

G8. A characters stats can modify his saving throws, as well as several other factors within the game. PCs with a high Wisdom should modify their saving throws against rods, staves, and wands, and against magical spells, based off of their magical defensive adjustment. PCs with a high Dexterity should modify their saving throws versus physical spells, based off of their defensive adjustment. As well, they should modify their initiative and their movement rates, based off of their reaction adjustment from Dexterity.

G9. Basic clothing, supplies, and some arms and armorment are given to the character at no cost, prior to gameplay. Armor up to chain mail, and weapons of no more value than one-hundred silver are included in this one-time freebie. This allows the character to spend his excess money on items or animals that further enhance his role-playing.

G10. People joining the campaign at later dates can generate characters using the house rules, notes, and modifiers. However, their level is always less than that of the other characters already present in the game; players should not be rewarded for late starts. PC's from other campaigns can always be adapted at the DM's discretion, provided the other players are amicable to the inclusion.

P1. A character's Intelligence determines the bonus number of proficiencies he has, determined from the 'number of languages'. For instance, a character with an Intelligence of 11 would have two bonus proficiencies; these bonus proficiencies may be spent for either weapon, or nonweapon slots.

P2. All characters receive one bonus, free nonweapon proficiency, determined by his secondary skill. A secondary skill may either be chosen, or rolled from the appropriate table in the Player's Handbook. This free nonweapon proficiency – the secondary skill – is something that the PC can do almost in his sleep; it's something he was raised in, and can perform almost without fail after three days without sleep, no food, and exhausting circumstances.

P3. PCs do not need to spend nonweapon proficiency slots on modern languages. They need only role-play learning new languages to accrue them, though the maximum number of languages they can learn is still dependant upon their Intelligence. PCs do need spend slots on ancient languages, for there are few (if any) people around to speak and practice the ancient language with. Some characters begin play knowing more than one language, automatically. Human characters might begin play with both Common (a trade language), and their native language; the same for humanoid races.

P4. The 'read/write' proficiency need only be spent once; it basically separates the literate from the illiterate. Even if additional languages are acquired by the character throughout a campaign, he need not spend additional slots to be able to read and write the new language. Ancient languages are a different matter, and PCs must spend nonweapon proficiency slots in the ancient language they wish to know.

P5. Multiclassed fighters may attain expertise, specialization, and even mastery of their weapons, though at a slower progression than straight fighters. Rangers and paladins, and other warriors as well, may advance in abilities, dependant upon their experience, and their levels. These restrictions on when certain warrior classes may attain abilities also applies to the tight and broad groups concept from The Complete Fighter's Handbook. Consult the chart below for details, where SW means 'Single Weapon', TG means 'Tight Group', and BG means 'Broad Group'.

* Additional slots need not be spent; however, significant weapons training is required.

P6. The nonweapon proficiency 'blind-fighting' allows a PC to fight in the dark, though he still has a -2 penalty to his THAC0, and cannot distinguish friend from foe merely by sound. Adding one slot to this proficiency upgrades it to 'ghost-fighting', reducing the penalty to THAC0 from -2 to 0; however, the PC still cannot tell the difference between friend and foe.

P7. Characters taking 'blacksmithing', 'armorer', or 'weaponsmithing' as nonweapon proficiencies receive a +1 bonus to their THAC0's with mauls and hammer-like weapons. This simulates their familiarity with the smithing hammer, and represents their long hours at the forge.

P8. Just as there are tight groups for weapons, there are tight groups for armor and shielding, as well. Spending one additional slot in either 'shields' or 'armor' allows that character all the benefits of the profiency (as per Player's Option: Combat and Tactics) with all shields or armors, representing their long hours at work with either.

M1. Wizards may wear non-metallic armors with no more than 3 points of Armor Class, base. Any heavier armor interferes with a wizard's somantic spells, regardless of Dexterity. Too much metal on a mage interferes with the normal flow of magic around him, and can lead to side-effects such as fizzled spells – or even frying the caster. Magical bonuses to armor, or non-metallic armors made from exotic sources, tend to be safe enough for the caster and do not interfere with spell-casting abilities.

M2. Magic users may pen scrolls at any time, not just at certain levels as specified in the Player's Handbook. Wizards have a base 10% chance to pen a scroll, plus 10% per level; this equals out to the 100% chance established by the books, at 9th level for wizards. Priests have a base 30% chance to pen a scroll, plus 10% per level; this equals out to the 100% chance established by the books to pen a scroll, at 7th level. Additionally, extremely high quality materials can increase this chance, and poor quality materials can decrease it. The bonus goes up to a maximum of 5% per, for good inks, papers, and quills. Substandard materials go up to a penalty of 5% per for these items, invoking a maximum -15% penalty to a magic user's chance to pen a scroll. The nonweapon proficiency 'scribe' gives a +10% bonus to this chance to pen scrolls, for either wizards or priests. In general, high quality items cost upwards of fifty silver and more.

M3. Higher level magic users may give up higher level spell slots, for lower level spells. The point system is used, so that one 1st level spell counts as 1 point, and one 2nd level spell counts as 2 points. One 5th level spell could be replaced by five 1st level spells, and five 1st level spells could be replaced by one 5th level spell. Magic users can never cast a higher level spell than their level limit allows.

M4. Cantrips and orisons are the heart of all magic users' repertoires. As such, wizards and priests have more of these spells available than stated in the books. One spell point can always be used to learn a cantrip or orison-quad, but these special slots available for cantrips and orisons can never be used for anything but.

M5. Summoning spells have an optional, additional component that gives the caster a greater degree of control on what type of creature he's summoning. By drawing a summoning circle on the ground, and standing within it, the caster may add additional runes or prayers to the circle that help him specify what terrain he wishes to draw a creature from, such as 'freshwater' or 'mountains'. (Use the 'random encounters' for the Sister Worlds to determine just what creatures are available for summons.) Without this additional component, the spell functions as normal.

M6. Invocation spells on Gaeleth, as cast by wizards, have a 24% chance of spell failure on Gaeleth (unless otherwise noted). Invocation spells are granted by deities, and are basically prayers made by the wizard to one god or another, as specified by the spell. Deities are not bound by spells, and can decide on their own whether to grant the spell or not.

M7. Magical bonuses to armor, such as the +2 to 'leather armor +2', also apply to certain saving throws. The bonus is applicable to saves versus physical spells and breath weapons, in addition to the bonus to Armor Class. Such modifications need to be reflected on the PC's character sheet, because they are often forgotten in the heat of battle.

M8. There are different psionicists for Jazed than are detailed in the books. Jazed has a wider variety of specialists in one devotion or another, in addition to psionicists never before seen. Details are available in the pages devoted to Jazed, but should be consulted should a character choose or roll well enough to play a psionicist.

A1. Characters are unconcious if reduced to zero Hit Points – not dead. PCs are only considered dead when their Hit Points are reduced to less than their negative Constitution scores. Characters with less than zero Hit Points, but still not dead, are considered to be dying; subdual damage can never lower a PC's or NPC's Hit Points below zero. Thus, a character with a Constitution score of 12 would be unconcious at 0HP, bleeding and dying at -4HP, on the edge of death at -12HP, and dead at -13HP. PCs that are dying can lose varying amounts of Hit Points each round, dependant on the extent of their wounds, but it is generally 1d4 per round, until the character is stabilized.

A2. Hit Points are a measure of endurance, and nothing more. Wizards have low Hit Points because they don't spend their time building up battle endurance, heavy in the training with sweat pouring off their brow. Warriors train, building up a lot of endurance – thus they have more Hit Points. In combat, Hit Points can be lost merely by blocking a blow; muscles strain, and can be worn out, without drawing blood. Roughly the first 80% of damage dealt to a character is merely Hit Points lost through fatigue, bruises, and normal wear and tear. The final 20% of damage dealt to a charcter is when the blood starts to flow, and an opponent's weapon actually starts to hit the character. This makes for more realistic combat, reflecting real-world endurance.

A3. Rolling a natural twenty for THAC0 implies more than a guaranteed hit. It means that the character deals maximum damage, plus the normal variable amount of damage for his weapon. Thus, a PC with a longsword and specialization might normally deal 1d8+2 points of damage to small and medium creatures; but with a natural roll of twenty, he would deal 10+ (1d8+2) points of damage. It's ridiculous for a character to roll a natural twenty, and deal minimum damage simply because of the die roll. On the other hand, it also puts genuine fear in a character, because the NPCs and monsters can deal considerably more damage to them than they would ordinarily.

A4. Rolling a natural one for THAC0 requires an immediate Dexterity check. If the Dexterity check fails, then either control of the weapon is lost, or the weapon must roll a saving throw versus crushing blows – or be destroyed. If the weapon is lost, it will require a minimum of one round to retrieve. A successful Dexterity check merely means that the PC missed – and rather badly, either due to weapon fault or some unforeseen means.

A5. Bribery is allowed. The old joke is that there are 'pizzas of ressurection' and 'colas of healing' scattered throughout the realm. In actuality, a DM should always give the occasional hint or boon to the characters without having to be 'bribed' with good-natured friendship, but just for the records, the ruling is there.

A6. Non-human PCs may exceed their usual level limits. The level limits ruling was placed in the books to give humans some sort of edge over the demihuman races with infravision, Constitution bonuses, weapons abilities, and the like. In the Sister Worlds, humans are simply the most versatile of races, mentally. They may not have heightened senses or racial tendancies towards Picking Pockets, but they can adapt their thinking in ways the other races cannot. This is why humans have unlimited level advancement. After a certain point, the other races take major readjustments in their world views in order to overcome their natural inclinations. Demihumans can exceed their level limits, but at the expense of Experience Points; they require double the number of XPs per level, after their limits have been reached.

A7. The DM should have a copy of all characters' current stats and levels, so that he can prepare upcoming games, make use of the PCs' strengths, and plague their weaknesses. As well, this allows the DM to post their stats on the the Web as a backup, against the inevitable, “I lost my character sheet!”

A8. Each time a character dies, it is a remarkable event. Ressurections and raisings from the dead do not occur all the time or everywhere, and they usually entail a great deal of work. But PCs do return from the dead – and sometimes, they bring something back with them. If a PC has made the appropriate saving throws or restoration rolls, then the DM secrety rolls one additional die before he can return to the living. He rolls a 1d12, with a 1 being good – and a 12 being bad. Consult the table below for details.