Are Legendary monsters in the Monster Manual ever able to be defeated?

Question

I'm starting my first 5e campaign soon and I'm just learning about balancing encounters. While looking up challenge ratings I noticed a very troubling truth:

Of 30 challenge levels in the Monster Manual, more than half of the monster ratings (all monsters CR 15-30) are considered beyond deadly for a party of four at max level, by themselves. According to DMG 82 on XP thresholds, 12,700 XP encounters are deadly for 20th level parties. All monsters at CR 15 or higher begin at 13,000 XP. In fact, by these calculations a Tarrasque is more than 10 times as deadly as any encounter that's expected to be lethal to a level 20 party, and its CR is twice what is considered rational for encounter planning. Dragons, Liches, and everything else between aren't much less daunting.

It's bad enough to have to wait for my party to reach double-digit levels before they take on Legendary monsters. But the fact that I can't expect to use one—ever—without a TPK just seems a little disheartening.

My Question:

Why do CR 15-30 monsters exist if they're designed to outright kill a party of any level with no contest? Is it a joke? It this just for GMs who hate their players? Or is there some secret loophole I'm missing that makes victory against Legendary monsters feasible?

Answer 1

Using an online Challenge calculator, I am not seeing the issue that you are describing.

Monsters exist up to CR 24, and then the Tarrasque by itself is 30.

For 4 Level 20 PCs, a single enemy of CR 23 is at the high end of a Hard encounter, just barely below the threshold for a Deadly encounter. A CR 24 is thus a Deadly encounter, but 5 Level 20 PCs push it back down to a Hard. (The Tarrasque requires 7 Level 20 PCs to push it under the Deadly level, but lets ignore that one! Using that, you are definitely threatening a TPK!)

I believe you are calculating challenge improperly. I will explain what I think you are seeing, and you can obviously correct me if I am off base.

For the CR calculations(using the table on page 82 of the DMG or page 56 of the Basic DM Rules), a level 20 PC has a Deadly threshold of 12700 XP. A single CR 15 monster is worth 13000 XP. Since that is higher, you see it as being a Deadly encounter. However, for encounter calculations, you must add in the XP threshold for each party member to arrive at your overall thresholds (which is explained in step 2 of the Evaluating Encounter Difficulty section on the same page as the XP Chart). For a party of 4 Level 20 PCs, the Deadly level is set at 50800 XP. A single CR 15 monster against a party of 4 Level 20 PCs will be an Easy encounter.

Answer 2

Because you are not meant to fight them head-on.

There are many monsters that are indeed lethal to fight head-on. For example, the Tarrasque has a history in Dungeons and Dragons as an extinction-level event and is capable of devouring all but the most powerful of parties, specifically engineered to taking it down. Many paries have tried over decades of gaming to take out Big T only for them to line its teeth very soon afterwards. So why is it statted? For two reasons:

• It is a device to cull dumb players. If they think that the four of them can kill what is essentially Godzilla, reality will swiftly ensue. If the players got upset they got eaten, point out that they wanted to take on Godzilla with just the four of them.
• It makes them technically beatable, but it won't be easy. The only way to make a head-on fight easier is by wearing a Cloak of Condiments +6 and hope you get eaten quickly. It forces players to think outside of the box, come up with tactics, methods and other ways to kill it.

Of course, there are many monsters in the 5e Monster Manual that work the same way. Dragons can easily kill you, and an Androsphinx can de-age you, send you back a month in time and have an early version of himself do it again, until you de-age back into a fetus and die. Or you get dropped onto the 222nd layer of the Abyss, have fun getting back home! All of this of course happens when you fight them head-on. So the solution is simple: DON'T FIGHT THEM HEAD ON.

As a DM you COULD point out to the players that the monster in question is too tough to beat head-on, but that would take away their agency (or they'd try anyway). Urge them (either IC or OOC) to find a workaround to kill them, either with in-game items or DM-crafted artifacts (and all the quests involved with finding them!) to defeat the campaign-level threats.

Answer 3

I think this has a lot do do with your party. If you have a bunch of dice rollers that just attack head-on and expect to win by believing in the spirit of the dice, then yeah they are overpowered.

HOWEVER, if your party is good at role playing and being clever or creative in their approach to challenges, then legendary monsters may very well be a perfect match for your party.

Think about this somewhat,

Answer 4

a) not everyone kills every monster they encounter. monsters can also be sources of information, resources, string-pulling machiavellis, etc.

b) challenge ratings are a guideline, not gospel. baseline PCs can take on a more-than-deadly adversary under specific circumstances or with a great deal of chutzpah and luck. and some campaigns and parties of PCs will be more powerful than baseline, and can take on more powerful adversaries.

Answer 5

1. Magical items could boost you into being completely immortal or having 8 elementals serving you; those could help you achieve victory.
2. Use range. For example, a level 5 party could beat a tarrasque, but they have to stay far away and snipe and restrain it a lot before having it come right at you. The strategy goes like this: Those in the party who have chosen weapons attack with crossbows and the feat Crossbow Expert. Spell casters use ray of frost to slow the tarrasque and attack with fireballs and lightning bolts dealing 8d6. Those with knockback spells like thunderwave could push it back when it came close.

But by far the best way to beat a tarrasque is to use true polymorph at lv 17 to turn the tarrasque into a bunny.