Article - Tips for Creating Challenging Monsters
by Drakefyre

At some point, you'll get tired of the general types of monsters and want
to create something more interesting, more challenging, and more
innovative. These are some general tips to make your monsters more
difficult without making them boring or repetitive. Depending on the degree
to which they're used, they can make any level scenario more challenging
and interesting.

1) The basic thing you can do is increase a monster's level, which will
greatly increase a monster's damage, health, spell points, and general
effectiveness. However, it doesn't do a lot to make them new and
interesting.

2) Experiment with melee attacks. Increase the melee stat and strength of a
monster and decrease the monster's HP or even the number of sides on the
dice for innate melee attacks. A 20d5 attack is much better than a 5d20
attack, and a 20d5 attack is more likely to pierce armor and do damage at
higher levels.

3) Increase the effectiveness of spellcaster AI by adjusting spell levels.
Using the call 'change_spell_level' you can adjust spell levels to 0, 1, or
3 (two is the default). Setting the spell level to '0' will mean that the
monster will never cast that spell, meaning that you can effectively choose
which spells a mage or priest will cast, reducing (or eliminating) the
amount of castings of woefully ineffective spells.

4) Use disabling special abilities. Disabling special abilities are ones
that limit the mobility and effectiveness of the party, like slowing,
cursing, webs, paralysis, confusion, et cetera. Paralysis should only be
used sparingly, since it will doom a singleton (one-PC party), which many
people play with. Still, webs, sleep, and slowing will allow your monster
to get extra attacks in, while slowing down the movement of the party,
forcing the player to use different tactics.

5) Target a certain type of PC. Using the dumbfounding ray special ability
will remove spellcasters from the battle, making the party use melee to
beat you. Using an antimagic field will also do it, as will adjusting
immunities. Likewise, giving a monster high armor and low immunities will
necessitate using spells to attack it.

6) Play around with monster behavior scripts. Stareye wrote a behavior
script called 'magekiller', which will make the monster attack the PC with
the highest amount of mage or priest skill. Other behavior scripts involve
regenerating, hasting, blessing, and other things that monsters shouldn't
be able to do but can. Be careful with some of them, though - making a
behavior script too powerful will seriously annoy the player.

7) Use the ray special abilities. Rays only take one AP to fire, and
they're a good way to put medium-level parties on the defensive.

8) Don't ignore the eight item slots you have! One of the most powerful
tools that designers have is the capability to equip our monsters with
weapons, armor, potions, scrolls, and more. Giant Chiefs in Avernum 3
quaffed an invulnerability potion before every battle. Giving an
invulnerability elixir to a warrior-priest will allow him to cast defense
priest spells without having to worry about dying for a few turns. Giving a
goblin a scroll with Lightning Spray will shock a low-level party. Tweaking
items and testing various combinations will ensure that you've got the
right balance for your scenario.

Still, all of these are only useful if they're used in the right setting.
Having an outdoor combat full of heat ray-firing ruby skeletons in a
beginner scenario will make anyone but the best players give up in
frustration. A more appropriate combat would be a few ghouls (disablers)
along with a ruby skeleton or two - slowing the party so that they can't
respond to the barrage of fire unless they quickly cast Repel Spirit. As a
player, I'd rather face a few interesting monsters used in combination than
slogging through tons of the same monster.

Note From Jeff Vogel:

Excellent article. A few suggestions I would add.

Even the strongest creature is weak if it's by itself. The best way to
spice up an encounter or make it more challenging is to add friends.

If a creature isn't doing enough damage to affect players, increase the
strength or melee weapons skill. The damage from innate attacks (like
clawing and biting) is increased by melee weapons skill.

Finally, an advanced trick. You can give a creature special abilities or
defenses by giving it an item. If you don't want the get that item, you can
erase it by using the destroy_char_item call in the DEAD_STATE state. (Note
there is a bug with this call. You can't use ME for which_char. Get the
creature's number using my_number.)

- Jeff Vogel
Spiderweb Software, Inc.
http://www.spiderwebsoftware.com