dave2008
Legend
The 2024 MM is mostly like a slightly improved 2014 MM. For example, bloodied is hardly ever referenced. It is not something special every creature has. Most of the monsters in 2024 are just revisions of the monsters in 2014. So basically all those 3PP books will still work with the 2024 MM to add options just like they would to the 2014 MM. With one caveat: Lair Actions.I was inquiring as I did, because the new Monster Manual is supposed to have variants for various monsters and reintroduce the Bloodied Condition. Bloodied and Bruised introduces Bloodied for 2014 MM monsters and the Monster Manual Expanded includes variants for the MM 2014 monsters. I threw in Home-Field Advantage (or optionally, Legendary Bestiary: Lair Actions for Low-Level Monsters), because it expands on Lair Actions for 2014 MM monsters and I don't know exactly what the new MM is doing with Lair Actions.
The 2024 MM does not have lair actions. Monsters are more powerful in their lairs (getting an extra Legendary Resistance and Legendary Action in their lairs), but no actions they can take on initiative count 20 like before. Additionally, in the 2024 MM the area around a creature's lair has effects similar to the 2014 Regional effects, but they have more mechanical impact than simply being "signs" of the monster like they were in 2014. For example, here the are for a red dragon:
The region containing an adult or ancient red dragon’s lair is warped by its presence, creating the following effects:
Burning Heat. The area within 1 mile of the lair is an area of extreme heat. A burning creature or object takes an additional 1d4 Fire damage at the start of each of its turns.
Smoldering Haze. The area within 1 mile of the lair is Lightly Obscured with clouds of ash. Whenever a creature other than the dragon or one of its allies finishes a Long Rest in that area, that creature must succeed on a DC 15 Constitution saving throw or have the Poisoned condition for 1 hour.
Burning Heat. The area within 1 mile of the lair is an area of extreme heat. A burning creature or object takes an additional 1d4 Fire damage at the start of each of its turns.
Smoldering Haze. The area within 1 mile of the lair is Lightly Obscured with clouds of ash. Whenever a creature other than the dragon or one of its allies finishes a Long Rest in that area, that creature must succeed on a DC 15 Constitution saving throw or have the Poisoned condition for 1 hour.
That being said, you can still use 2014 style lair actions if you want. I find them more interesting than the 2024 approach and will continue to use them myself.