Not every enemy needs a super unique mechanic to be built around the new legendary resistance mechanics. Some enemies have gimmicks that do not translate well into this framework, some enemies only are meant to be minibosses on the player’s journey rather than the centerpiece of an encounter at the story’s climax, and sometimes you just don’t have time to prep and need something quick and easy to slap on an enemy to increase its resilience or lethality. Whatever the case is, here are two simple mechanics that can be put into almost any encounter, still force the players to be mindful of the legendary resistance mechanic, but also won’t take center stage in the combat:

Generic Resistance mechanics:

Storied Resilience – X/X uses (X is the number of players in the combat). When an enemy with this feature has leftover legendary resistances at the beginning of its turn, it gains Y temporary hit points for each resistance left unspent (Y is equal to the party’s level plus their proficiency bonus). 

Storied Lethality – X/X uses (X is the number of players in the combat). When an enemy with this feature has leftover legendary resistances at the beginning of its turn, it gains that many points of Danger. When this creature deals damage to one or more creatures, it can spend a point of Danger to deal an Y points of damage to each creature that was damaged (Y is equal to the party’s level plus their proficiency bonus). Any stacks that are unspent at the beginning of its next turn are lost.

These formulas can be plugged into most combats for a relatively balanced fight in a vacuum, but a few extra rules can help you achieve better balance as the circumstances change:

• If the boss enemy using these legendary resistances has additional enemies backing them up, drop the number of legendary resistances they have (X) by 1 for every two average enemies they have with them, or every four weaker enemies.
• If the players fighting the boss have allied creatures with them, I add legendary resistances to the boss. I add one resistance for every allied creature roughly equal to a player in power, two for each greater ally, and one for every two weaker allies. If the players have a bunch of extremely weak allies (say villagers defending their home), I only add one resistance.
• If there are multiple boss enemies in the encounter with legendary resistances, I usually balance their total legendary resistances around this formula, and then split the resistances between the creatures as appropriate.
• If I am creating or converting a statblock that is intended to be a resilient enemy, but not one that is the focus of the encounter (a mini-boss of sorts), I will usually give them only 1 or 2 legendary resistances at most. 

• Note that the numbers are balanced around From the Pale 5e’s buffs to player characters across the board in terms of damage output, abilities to negate damage, and ways to force saving throws from the enemy. I would tone down the numbers a little bit if you are only taking this idea for your game —at least until you are able to get an idea of how the mechanic plays at your table.

Converting monster stat blocks which already have legendary resistances:

When a monster statblock is being used with these legendary resistance rules I make changes to monster statblocks if it has the following traits:

• Magic Resistance
• Legendary Resistance (any number per day).

Unless I intend to use a unique legendary resistance mechanic for that creature, I will give it generic legendary resistances instead.

• If the creature is known for its toughness, like an Iron Golem, I will lean into that and give it Storied Resilience.
• Similarly if a creature is known for its danger, like a Balhannoth, I will lean into that and give it Storied Lethality.
• Otherwise I usually aim to balance out the statblock (or the encounter it will be in) by giving it Storied Resilience to bolster weak defenses, or Storied Lethality to increase a tanky boss’s threat to the party. 

• When replacing the aforementioned features, I give them legendary resistances like so:

Feature/s	Legendary Resistance Formula (where “X” is the formula as laid out above)
Magic Resistance	X-2
Legendary Resistance (1/day)	1 Resistance for a party of 4 or less. 2 Resistances for a party of 5 or more.
Legendary Resistance (2/day)	X-1
Legendary Resistance (3/day)	X
Legendary Resistances + Magic Resistance	X for 1 Legendary Resistance/Day, X+1 for 2 Legendary Resistances/Day, X+3 for 3 Legendary Resistances/Day