[RPG] How to scale up a monster for a large party


I am DMing a game for 6 PCs who are currently level 5.

During gameplay, even high-CR monsters have been easy pickings for them due to their advantage in numbers. They are starting to underestimate single-monster encounters.

I don't want to always try to match the monster numbers (because sometimes it makes sense that that particular opponent is alone).

Problem to solve

I don't want to shower them with hordes of monsters at every encounter. How do I scale up some of the more story-driving monsters for a more memorable campaign?

Best Answer

You should totally scale the single-monster encounters to make them memorable for everyone. You have multiple options for that.

Lair actions

If your single monsters are bosses or the like, you can give them lair actions. Just look at examples like the dragon ones (starting at MM 86). Rambling terrain, furious waterfalls, tempest winds, make your choice.

Modify your monsters

Read the chapter Modifying a Monster in the DMG 273. You can adjust simple things like giving immunity to a certain type of damage to the monster, give it a flying distance, give it better weapons (maybe even magical lootable ones!), or give it additional features (pick one from the DMG 280!).

Making a bigger version of a monster can also be a thing (like modify a medium monster into a large one). This will increase its hit points and also allow it to do more damage using weapons (x2)! (see Step 11. Damage DMG 277-278)

You can then re-calculate the challenge rating of your monster and make sure it is appropriate for your party !

Add minions

Powerful monsters don't always act alone. They often have hordes of minions at their command, and even bodyguards or lieutenants! If you don't want to add too many monsters to encounters, as you mentioned, you could give a try to the latter options! Simply add one or two less/much less powerful monsters to the fight, and this should rise the overall challenge rating of your encounters!