Carrier attacks and status effects can be used to complicate a battle and increase a monster’s threat level. But be careful not to overuse them.
When NPCs are armed with carrier attacks and status-effect abilities, it drains certain player resources. Be careful not to overtax specific resources by sending out too many of the same status effects. Be aware of which skills the players are using up to resolve the damage they’ve taken.
For example, charm, sleep, and fear effects are all cured by Awaken spells. If you’ve been sending out willow-the-wisps with charm spells and creatures with sleep carriers all day, think twice before sending out more creatures with fear carriers.
Carrier attacks become very frustrating when you’re hit by them too often, or when you must simply endure the effect because a cure isn’t available. If nobody’s willing to unparalyze you, you might up spending 10 minutes as a statue every time someone hits you. That’s not a very fun way to spend a fight.
As a rule of thumb, no more than a third of the monsters in a group should have take-out carrier attacks. Those monsters with carrier attacks should do lower damage than the other monsters, making armor and protective spells useful defenses.
When using monsters that deliver status effects, set up tactics they will use to maximize the effect. For example, giant spiders which web their opponents might be paired up with archers who pelt helpless targets with arrows. A PC that is diseased and feared is only walking away from the fight and is therefore very vulnerable to rogues. Disarm + fear is a nasty combo as well, as it sends an unarmed character running across the battlefield.
Be especially reserved in using spell strikes and massive damage, as there are few ways for players to avoid these attacks. Being targeted by them is frustrating because the monster doesn’t need to land a fair hit for the attack to work.
Massive damage, a type of damage which cannot be blocked by weapons, was originally meant for traps but has been used increasingly frequently as a monster ability. In order ot deliver it with a trap, you generally need a large impressive prop to justify why you can’t block the blow.
Massive damage delivered by weapon lacks this atmosphere and therefore should be uncommon at best. When it is employed by a creature, that creature should have props, roleplay, or costume which communicates the creature’s size and strength. Maybe when they deliver a massive swing they must roleplay a slow, powerful swing, giving players time to dive out of the way.
When using massive damage, keep in mind that you’re not really fighting fairly, and this can be no fun for your opponents if you use your ability too liberally.