“Masteries” are a category of skills that grant direct power bonuses to one or more of your skills and spells. For example, ‘mastery of medicine’ boosts the amount healed by all ‘heal’ spells by a large percentage.

Although the effects of masteries can vary wildly, they almost always give far greater benefits than what can be had by 100% ability in what they modify. In most cases a mastery skill will add at least an extra 50% to the power of what they influence when maxed out.

Some masteries will also cause special effects or extra abilities to become available. For example ‘knowledge of identification’ will cause the identify spell to give highly detailed bonus information about materials.

Between changes to the game, guild customizations, reputation systems, special bonuses, and passive skill modifiers, there is actually a lot of gray area as to what skills are actually “masteries” in the classic sense of the term. For example ‘Essence of corrosion’ is an extremely useful modifier of acid spells, but is not their mastery in the classic sense, but a newer reputation bonus for acid mages.

As a rule, true masteries always give a straight power boost. They’re usually named accordingly: Skills named “theory of …”, “mastery of ..”, “knowledge of …” are generally classic mastery skills. They’re a mechanic that is older than the ‘new’ reputation systems, and will tend to be less dependent on how long you’ve been in any given guild.

All spells are associated with a specific type of magic. Fireball is a fire spell, spark birth is a rift spell, and mirror image is a protection spell. To cast, say, fire spells reliably, you will need skill in both cast generic and cast fire. Your skill in cast fire will of course do nothing for your ability to use teleportation magic.

The type of spell also determines if a particular mastery or guild reputation bonus can benefit the spell. Mastery of arctic powers will do wonders for the cold spell ‘cold ray’, but it won’t do anything for the rift spell ‘rift pulse‘ even though both do cold damage.

Your character can only lift so much weight before nothing else can be picked up. Even if you’re below this limit, carrying lots of stuff around can have negative consequences. You can transport more items by using a mount with saddlebags, rigs, floating discs, and other means.

Players use the following formulae to approximate how much they can carry:

Burden starts kicking in at: 33+strength/3 kilograms
Maximum carrying capacity: 50+strength/2 kilograms

There are many ways in which you can find yourself exceeding your maximum carrying capacity. One simple example is if you have your strength magically reduced. If you go too far over your max, you’ll tend to start dropping things. The game will try to start with items in your inventory that aren’t on your keep list, to reduce the chances of dropping valuable gear.

The bulkiness of an item also has some effect, but weight is most important.

Being burdened negatively impacts many skills, not the least of which are swimming and hiking. It can also slow spellcasting and reduce your defensive rating.

Not to be confused with there being a maximum number of items that can be carried, which is a concession to keeping the game from being lagged rather than a balance issue.

This is a quick paste of my old banes guide. As you can see it needs a rewrite. I’m putting it here as is to be a stub for linking to.
Help on Banes:
Note: Bane severity is currently disabled in game.
Each bane can let you pray for some level of a boon. Before February 02, 2004, all banes only gave 10 tps toward a boon, but now they grant additional strength if they are particularly nasty.
This permits those without taskpoints to get a little versatility, but at a cost. Banes used to allow one to enhance a boon to 110% effectiveness, but this option was eliminated in late 2003. Most players will generally have access to a couple of banes that they will consider to be of inconsequential negative impact, but no bane is harmless to everyone.
As a rule of thumb, banes that can cause damage are not worth your time.
Acne:
Makes you more prone to scars.
Availability: civilized, magical, nomad, good_religious and evil_religious backgrounds
Severity: mild nuisance (1)
Acne makes it more likely that death will leave you physically and mentally scarred. With acne, it remains possible to die and avoid scarring, but most deaths will bring a few scars, and you will sometimes be stricken with six or more. For those who have the funds to maintain a high charisma and do not die frequently this is an inoffensive bane. It is significantly more dangerous for those who would fight powerful monsters for their equipment, since such battles bring death frequently, and you simply might not get the opportunity to keep your charisma at safe levels.
Afraid of the dark:
Makes you afraid of dark.
Availability: civilized, magical, nomad, good_religious and evil_religious backgrounds
Severity: mild nuisance (1)
Your character will become fearful in dark places, and will try to flee from them from time to time. Carrying light sources is the only way to prevent this from happening. Even magic that grants infravision will not quell this fear. Races which can see in the dark cannot take this bane. This bane makes it arduous to party with races that are allergic to light, and should something overpower your light source, you may wind up fleeing into a powerful monster.
Brain fever:
Makes all your spells go to 0% occasionally.
Availability: civilized, magical, good_religious and evil_religious backgrounds
Severity: generally annoying (2)
Brain fever will randomly cause your spells to be reduced to 0% for brief periods. How annoying or dangerous this is to a character is directly proportional to how often it plans to use magic.
Clumsiness:
Increases your chance of fumbling attacks.
Availability: civilized and nomad backgrounds
Severity: mild nuisance (1)
In the old days, it was fairly common to fumble normal attacks, usually by hitting some random target in the room. This was similar to how a fumbled blast can hit the caster or a friend. Since fumbled normal attacks don’t exist anymore, and most off skills just fail or succeed, I have no real idea what this bane is supposed to do, though I have theorized it may cause your weapon to take damage much more often.
Clumsy death:
25% chance you drop all carried items when you die
Availability: civilized, magical, nomad, good_religious and evil_religious backgrounds
Severity: almost impossible to tolerate (4)
Perhaps a good way of donating valuables to whomever kills you.
Drifter:
Makes your character’s alignment change more easily.
Availability: civilized, magical, good_religious and evil_religious backgrounds
Severity: mild nuisance (1)
Until 31/08/2003, this bane actually didn’t do anything, existing as a true freebie. Now days it damages you if you are neutral, seems to rarely make you turn neutral, and perhaps adds to the chance of your alignment changing from spells and deeds. This bane remains pretty benign to most characters however.
Dyslexia:
Makes you occasionally miss training and studying sessions.
Availability: civilized, magical, nomad, good_religious and evil_religious backgrounds
Severity: mild nuisance (1)
When training or studying, you will sometimes spend experience on a skill or spell, but fail to see it improve. This seems to happen about 10% of the time. The experience will be lost until you reincarnate, at which point you will regain it, though it is subject to normal reincarnation taxes. This bane can also negate the rise of a skill from use. This latter effect can cripple merchants and monks, who can only master some skills by using them. Typically this bane is only taken by the very ignorant or after one of the best players in the game has finished a reincarnation.
Fast aging:
Makes you age faster.
Availability: civilized, magical, nomad, good_religious and evil_religious backgrounds
Severity: mild nuisance (1)
This bane makes your character more vulnerable to aging, especially from the strain of being restored to life after dying. Many players won’t notice any difference, as they reincarnate enough that age is not a concern to them. Those who wish to remain in the same reincarnation for long periods of time will find this bane much more harmful however, as it will make staying youthful difficult. Your race also has a huge impact on how harmful this bane is. Zombies don’t even notice it, Thrikhren could never safely take it.
Feminism:
Makes you attack non female characters without any apparent reason.  If you
aren’t female yourself it works the same way as the bane ‘You don’t want this
bane’.
Availability: civilized, magical, nomad, good_religious and evil_religious backgrounds
Severity: mild nuisance (1)
You will very frequently attack male characters, monsters, and animals for no particular reason. If you take this you will need to be very wary of sex change spells. Even if you apologize nicely to those characters you attack, it’s still a bad idea to take this, since you might attempt to kill Grimoor, Sable, or another big nasty guild master with sharp, pointy teeth. Not a good bane to take unless you can live with all the consequences involved with randomly going berserk every five minutes.
Machismo:
Disables your ability to be wimpy.
Availability: nomad backgrounds
Severity: mild nuisance (1)
This disables your ability to wimpy, and makes it impossible have your character instantly flee combat should it take large amounts of damage. Most players are of the opinion that nomads should never set wimpy anyway, and consider this bane to be almost obligatory.
Masochism:
Makes you sometimes take more damage.
Availability: civilized, magical, nomad, good_religious and evil_religious backgrounds
Severity: mild nuisance (1)
Your character has an affinity for pain, and when taking damage, might just decide to suck down far more than it normally would. I’ve seen back row characters with decent hit points get felled by quite small blasts because of this bane. This bane is held in almost universal contempt.
Modesty:
You can’t use any skills or spells if you aren’t wearing decent clothing.
Availability: civilized, magical, good_religious and evil_religious backgrounds
Severity: mild nuisance (1)
I haven’t had this one in a long time. I think it makes you unable to use skills without all eq slots filled. Possibly this only happens around other players, I need to test it sometime. Probably not too hard to overcome, but it would hamper in a number of special situations, such as trying to fight a monster that dests.
Moon madness:
Makes your spell point costs slightly unpredictable.
Availability: magical, good_religious and evil_religious backgrounds
Severity: mild nuisance (1)
A brief, non-scientific test of this bane showed that it often made spells cost more spell
points, and sometimes caused no change or made them cost fewer spell points. It appeared add roughly 3% to spell point costs over time. This bane does seem to essentially raise spellcosts, not make them random.
Occasional Paralysis:
Makes all your skills go to 0% occasionally.
Availability: civilized, nomad, good_religious and evil_religious backgrounds
Severity: generally annoying (2)
Occasional Paralysis will randomly cause your skills to be reduced to 0% for brief periods. How annoying or dangerous this is to a character is directly proportional to how often it plans to do anything besides idle.
Paranoia
Clinically, paranoia is characterized by highly systematized, persistent,
incapacitating delusions of persecution and/or grandeur; commonly used to
describe hypervigilence over a (mis)perceived threat, belief that danger is
everywhere, and belief that those who do not recognize the threat are evil and
part of the threat themselves.
Availability: civilized, magical, nomad, good_religious and evil_religious backgrounds
Severity: would be mild nuisance, but I doubt we’ll ever see bane severity again.
Whenever someone looks around, it will seem as if they are looking at you. Whenever someone uses a skill or spell, it will appear to be offensive.
Painful death:
25% chance you lose all experience (except safe exp) when you die
Availability: civilized, magical, nomad, good_religious and evil_religious backgrounds
Severity: major pain (3)
A bane for highbies who have maxed everything they care about, and people don’t live and die by their experience totals. Also appropriate for those who just don’t die very much during experience parties. This bane is probably common among rebirthers.
Racism:
Makes you attack players of other races or get outbursts of rage (damaging
you) when accompanied by players other than your party members of other races
occasionally.
Availability: civilized, magical, nomad, good_religious and evil_religious backgrounds
Severity: mild nuisance (1)
Reputedly second only to “You don’t want this bane” in nastiness, this is said to kick in much more frequently than the description implies.
Seasickness:
Makes you take a lot of damage occasionally, if you are in a room that
contains water.
Availability: civilized, magical, nomad, good_religious and evil_religious backgrounds
Severity: mild nuisance (1)
You will sometimes take large amounts of damage in water filled rooms. This bane
is far nastier than the water allergy that several races have, but doesn’t seem to be triggered very often.
Shyness:
Makes you occasionally afraid of other players.
Availability: civilized, magical, nomad, good_religious and evil_religious backgrounds
Severity: mild nuisance (1)
You will find yourself fleeing other players. As with all “flee” banes, the danger here is
dashing into something aggressive and bigger than you can handle.
Slow motion mouth:
Makes your spells go off slower than they should sometimes.
Availability: civilized, magical, good_religious and evil_religious backgrounds
Severity: generally annoying (2)
This can prolong spell casting to absurd lengths. Reliable spellcasting during combat becomes almost impossible, and even when not in combat your character’s magical abilities will be greatly hampered. Few people would be advised to take this bane, it’s effects are very detrimental.
Spell madness:
Makes you sometimes cast the wrong spell.
Availability: civilized, magical, good_religious and evil_religious backgrounds
Severity: mild nuisance (1)
If you cast a spell, there is a random chance you will try to cast another randomly selected spell you know instead, such as ‘harm body’ instead of ‘cure serious wounds’. This has the same basic uselessness of slow motion mouth with the romantic
addition of actual danger to the caster and his friends.
Weak heart:
Makes your character’s heart miss a beat every once in a while.
Availability: civilized, magical, nomad, good_religious and evil_religious backgrounds
Severity: mild nuisance (1)
This bane adversely effects your heartbeat, which has a negative impact on how fast you tick, how fast your spells and skills go off, and a few other factors. Though I have no idea how often this bane kicks in, heartbeat penalties are considered to be profoundly awful by most players.
You don’t want this bane:
You don’t want this bane.
Availability: civilized, magical, nomad, good_religious and evil_religious backgrounds
Severity: just plain evil (5)
Causes you to explode on a regular basis. This is
instant death for most people, but beefy hit points (750+) can let you
survive. It is possible for armor to dampen the blow (perhaps it
holds you together). The timing is fairly random, but you will usually wind
up decorating the landscape every half hour at least. In the game as a joke. You don’t want this bane.

BatMUD reduces the experience value of monsters that are constantly being killed. If you personally kill a monster, it will be worth moderately less experience for you for a while. This is called your personal tune on that monster. It will also be worth a little bit less experience for every other player until some time passes. This is generally referred to as the global tune. You can see the total of these two variables by using the consider skill at a monster.

Try to avoid killing any monster more than once per day if all you’re after is experience. If it’s a cash or equipment monster, then of course you may want to kill it whenever it’s available to slay, but you’ll note that you get very little experience compared to its difficulty.

Where this gets complicated is in what counts as the ‘same’ monster. Some monsters are ‘clones’ of each other, and killing one reduces the value of them all. Common signs of this are the monsters having the same or very similar names and being in the same area. Some wizards create a unique individual monster for a group of monsters with the same name though, so the only way to know for sure is to pay close attention and keep track of things with the consider skill.

The reason for this mechanic is to keep players from camping the same areas over and over again. Before this existed, it wasn’t rare for high end players to for example stomp all the Duzes in duzelton, all the guards in Shadowdale, and all the animals in Eowyn, and never leave those three areas.

There are two main varieties of ‘maze’ in batmud. The simplest is a randomly generated set of rooms that tend to have a confusing layout. An example of this style of maze would be the Arelium sewers. These are mazes in the sense that they can take some time to navigate. Generally they can be solved either by mapping, or by simply wandering around.

The second style of maze breaks down the traditional movement logic, such that if you go north, going south again may not take you back to the previous room. These mazes require you figure out where each exit actually leads in order to find your destination. These mazes can almost never be solved by wandering around. Often you’ll find what you’re looking for, but run right past it and be unable to retrace your path.

The standard method of solving type 2 mazes is by dropping coins. 1 mowgles coin in room 1, 2 mowgles coins in room 2, and so on. You can then map out where each exit goes, either with a program or with old fashioned graph paper. If you have the clairvoyance ability, you can work more quickly by only entering rooms empty of coins.

Not to be confused with maize, a cereal crop used in many products.

When entering a fight with a monster, especially aggressive monsters, it’s possible to become ambushed and unable to walk out of the room for up to 3 rounds.  This is a particular problem for newbie explorers, who don’t know where an aggressive monster might be, and have the least ability to survive.

There are ways to avoid or resist being fully ambushed. Having high dexterity, intelligence, alertness skill, and being small sized are all things which can help avoid ambush.