If you’re like most DMs out there you’ve probably run a combat with enemy spell casters at some point in your games. Inevitably, the first time a DM tries this something almost always goes wrong. Mages are particularly hard to use in combat scenarios in D&D because they can so easily tip the scales of combat by either making the fight too hard or they can be popped in one hit if mispositioned, leaving the combat stale and flat.
So how do we use spell casters more effectively in D&D combat?
Understanding Casters as Enemies
First we need to understand the roles that enemy spell casters play. This can be tricky because their role is heavily dependent on the spells they know and can cast. Agnostic of spell selection, let’s start with the things we know about casters in general.
Casters are typically lower strength, lower constitution enemies. Their highest stats are often Intelligence, Wisdom, and sometimes even Charisma. Almost every caster you use will have an above average Dexterity, but this is variable based on the type of caster you’re using. Most casters are ranged units with lower health, so having a higher Dexterity makes sense as it boosts their AC and helps them avoid death.
Now let’s break down what these stats actually mean for us in combat and how they shape the use of the casters as enemies.
Caster Decision Making
Combatants with higher Intelligence and Wisdom are often in a position to make better decisions about their actions. They will know who to target and will prioritize winning strategies. This also means they won’t hesitate to open with their most devastating attacks. If they have a spell that will increase their odds of victory, they’ll use it right away.
Another thing that wise caster enemies will do is keep their distance. They will wait for targets to come into range and they know not to get into melee range if they can help it. This is actually one of the big issues we run into as DMs. Planning a large enough space for combat to take place in can be a real pain. If you’re running a small, cramped dungeon where the largest rooms are a 50ft square, casters are going to have a really hard time without a lot of support enemies to run interference for them. And casters know this, so they will work to avoid being in those sorts of situations.
Smart casters will also know which attacks they have are most effective. This means that they will almost never use actual weapons. Any combat cantrip will be better than most handheld weapons that any humanoid caster would use. The exception to this would be cases where they understand that they cannot cast or are in a position to be punished heavily for doing so.
What this means for you as a DM is that you need to do the math and work out which attacks they have and figure out the conditions under which they would use each. It seems like a lot of work upfront, but it’s entirely reusable and often can be applied to other casters you use in the future.
With the exception of casters from religiously devout groups that may fight to the death like cultists, most casters are smart enough to run away when they know they’re going to lose. See our video on running away for more information on that. Most intelligent enemies will have an understanding of their own mortality, but casters are likely to run earlier than other enemies as they are acutely aware of their own strengths and weaknesses.
Now that we understand a bit more about how casters use their smarts for combat, let’s talk about how they would shape an encounter.
Using Casters in Encounters
Casters who are likely to be in combat situations never want to be alone. They are often backup for stronger units that can shield them from a fight and draw attention. Furthermore, casters may try to optimize a fight by leading the group. A caster leading a bunch of idiot fighters may be able to lead them to be more effective as a fighting group. This won’t always be the case, as sometimes the casters will be in a group they don’t want to be. In these cases where they cannot optimize a battle or the others in the group don’t respect their authority, they’re more likely to surrender if they think it will improve their situation.
Casters who have more authority or are in smarter groups of enemies will seek to position themselves where their abilities have the most use and impact. They prefer fighting in larger rooms or open spaces and will encourage this in their group when they are able. They will aim to be in the back when in indoor combat, or the center of their group when fighting outside.
Casters also seek opportunities for AOE damage whenever possible. Because of this, their group may focus on fighting tactics that attempt to cluster up the players. A particularly brutal fight might involve an NPC Druid coupled with a Mage. Two NPC caster enemies who can cast Entangle and Fireball respectively!
Caster Encounter Options and Spell Knowledge
When you are using a caster in combat you should seek to understand the full range of spells available to them, be it a monster with spells & spell-like abilities or a humanoid NPC caster. Knowing these will tell you what their effective fighting range is, and how far they should try and position themselves from combat.
Additionally, you will be able to learn which spells can be used as bonus actions or not, which is critical to how they fight. You cannot cast a spell as a bonus action if you’ve already cast a non-cantrip spell. In practice this means that casters will try to pair cantrips with spells that can be cast as bonus actions when they are in dangerous situations, allowing them to take the most actions they can with their turn.
As an example of this, the Mage enemy can cast Misty Step as a bonus action. In turns where the enemy is too close to them they will use Fire Bolt, their damage cantrip, and then use Misty Step to move an additional 30ft away from the enemy. This preserves their range, keeps up the damage output in the fight, and is imperative to the caster’s survival.
Also worth noting, Mages can only do that trick three times maximum, and may look at options to flee after they run out of this as a survival option. Misty Step will also be a spell worth preserving, so the Mage will likely avoid using other spells in that spell slot group.
Priests are a lot like mages and are wise casters, but their role is different based on their spell selection. A priest is supporting stronger fighters with healing, but also prioritizing staying alive (depending on their religious leanings). A priest has different defensive options, but included in these are Spirit Guardians to ward off enemies, and Spiritual Weapon which they can cast as a bonus action alongside their Sacred Flame cantrip.
Priests are no joke in combat and they have a pretty big damage output if they are forced to use it. So keep in mind that just because they’re NPCs of a religious following doesn’t mean they’re not dangerous. The main difference between a Priest and a Mage is that Priest will prioritize staying near their party and work harder on keeping other party members alive rather than seeking to add distance and sling spells from the back.
Both these example casters have similar ideas about how combat should flow. They both don’t want to get hit and are in the back or middle of their group, even if they are at different ranges. They play differently because you need to think about their abilities and how they are used.
Spells aside, they are similar, but once you get the spells in there you can see a different action plan unfold as their options for victory change. Mages win through higher damage output while Priests win through keeping their party alive longer.
Use Casters More Effectively
As a DM, understanding how to use every type of enemy in combat will not only make your games more fun, but it will also help you understand how to challenge your players more appropriately. While you shouldn’t be building campaigns that are outright trying to murder your players, you also should give them room to show off their abilities and look heroic by putting up a good fight for them.
We sincerely hope this makes your combat a little bit better.