Archdevil Moloch (Mordenkainen's tome of foes preview from Dragon+)

[Iry]

And beating them up or better yet use breath of despair on them. As this has a good chance of taking the backline out of the fight. Guys like the Cleric and Wizard who could cause problems. If this succeeds victory for Moloch is near certain. As he can use his superior mobility to keep the frightened characters trapped. While focusing on taking out the paladin or anyone that could cause him problems.

Even worse. He has At Will Geas. Anyone who fails their Wisdom save against Moloch becomes charmed and cannot attack him for 30 days. Remove Curse isn't common. Greater Restoration is, but then you're burning a 5th level slot to counter every Geas he casts.

Even worse. If he does get away? He can Alter Self and come back later to use his decent Deception + Charmed always giving him Advantage in social rolls to screw with you. Or blend into crowds and cast more Geas on you, until everyone in the party is eventually screwed. His mobility is so immense that he can literally pick your entire group apart piece by piece over several days, never even letting them rest.

 

[MonsterEnvy]

Even worse. He has At Will Geas. Anyone who fails their Wisdom save against Moloch becomes charmed and cannot attack him for 30 days. Remove Curse isn't common. Greater Restoration is, but then you're burning a 5th level slot to counter his geas every single round.

Even worse. If he does get away? He can Alter Self and come back later to use his decent Deception + Charmed always giving him Advantage in social rolls to screw with you.

Geas still has a 1 minute cast time.

 

[Iry]

Geas still has a 1 minute cast time.

It lasts 30 days. He has ample time to cast it repeatedly any time he can blend in with a group of people, or waste your time long enough with undead minions, which he can constantly replenish as long as the bodies last. He's an absolute nightmare for almost any group over a period of a couple of days.

 

[dave2008]

A CR 21 monster needs to be an even match to a party, at least, level 20. ESPECIALLY if it is legendary. That's what the CR is for. One level (especially one level up to the MAXIMUM level of the party) should be more than an even fight. And a CR 21 certaintly don't need to be an easy fight for a 20th level party.

CR doesn't = party lvl. That is not what CR means, Feel free to re-read the DMG section of encounter design (pages 81-85 in particular), there is even a little sidebar about CR.

Now, looking at the encounter XP budget in the DMG. A Hard encounter for 4 lvl 20 PCs = 34,000 XP, which is a little over the budget of the Moloch, so this fight would trend to Medium. As a reminder a Hard fight: "Weaker characters might get taken out of the fight, and there is slim chance that one or more characters might die."

That is not an even fight. An even fight would have to be Deadly which is: "...could be lethal for one or more player characters. Survival often requires good tactics and quick thinking, and the party risks defeat."

Deadly is the only option with a risk of defeat and thus an "even" fight.

For four 17th level PCs the Deadly budget is: 35,200, just a bit more than Moloch's 33,000. So Moloch, per the DMG, is an even fight for 4 16-17th level PCs.

FYI, an even, aka Deadly, fight for 4 20th level PCs is 50,800 or a about CR 23.

 

[MonsterEnvy]

It lasts 30 days. He has ample time to cast it repeatedly any time he can blend in with a group of people, or waste your time long enough with undead minions, which he can constantly replenish as long as the bodies last. He's an absolute nightmare for almost any group over a period of a couple of days.

I thought you were talking about In combat. Were it is not best used.

 

[Parmandur]

Moloch is not a white room superstar, but played to character is pretty astoundingly dangerous.

 

[Erechel]

CR doesn't = party lvl. That is not what CR means, Feel free to re-read the DMG section of encounter design (pages 81-85 in particular), there is even a little sidebar about CR.

Now, looking at the encounter XP budget in the DMG. A Hard encounter for 4 lvl 20 PCs = 34,000 XP, which is a little over the budget of the Moloch, so this fight would trend to Medium. As a reminder a Hard fight: "Weaker characters might get taken out of the fight, and there is slim chance that one or more characters might die."

That is not an even fight. An even fight would have to be Deadly which is: "...could be lethal for one or more player characters. Survival often requires good tactics and quick thinking, and the party risks defeat."

Deadly is the only option with a risk of defeat and thus an "even" fight.

For four 17th level PCs the Deadly budget is: 35,200, just a bit more than Moloch's 33,000. So Moloch, per the DMG, is an even fight for 4 16-17th level PCs.

FYI, an even, aka Deadly, fight for 4 20th level PCs is 50,800 or a about CR 23.

Even isn't deadly. Even is 50%-50%. Even is a fight in which each side has equal opportunity to win. It isn't the USA bombing Bolivia. It's a full scale war between China and USA. Is a football match between Argentina and Brazil.

 

[dave2008]

Even isn't deadly. Even is 50%-50%. Even is a fight in which each side has equal opportunity to win. It isn't the USA bombing Bolivia. It's a full scale war between China and USA. Is a football match between Argentina and Brazil.

Erechel, do you realize I am using a game specific jargon when I say "Deadly?" Note the capital "D" i used to denote the game rule term. The encounter guidelines in the DMG use the terms Easy, Medium, Hard, and Deadly to describe a type of combat encounter. Of the game definitions for those terms, the definition (in the game) for Deadly is the only one that constitutes anything close to an "even" fight. Per the definition in the DMG, a "Deadly" fight is the only type of encounter where there is a risk of failure. There must be a risk of failure for it to be an even fight.

So, in game terms, the closest we can get to "even" in the encounter guidelines is "Deadly." Thus, Even = Deadly. Deadly is the closest we can get to 50%-50% in the encounter guidelines in 5e.

 

[neogod22]

Even worse. He has At Will Geas. Anyone who fails their Wisdom save against Moloch becomes charmed and cannot attack him for 30 days. Remove Curse isn't common. Greater Restoration is, but then you're burning a 5th level slot to counter every Geas he casts.

Even worse. If he does get away? He can Alter Self and come back later to use his decent Deception + Charmed always giving him Advantage in social rolls to screw with you. Or blend into crowds and cast more Geas on you, until everyone in the party is eventually screwed. His mobility is so immense that he can literally pick your entire group apart piece by piece over several days, never even letting them rest.

What do you mean "if" he can only be permanently killed in Hell, which is the one place he will never attempt to fight since every time he goes there he's turned into an imp.

 

[Iry]

What do you mean "if" he can only be permanently killed in Hell, which is the one place he will never attempt to fight since every time he goes there he's turned into an imp.

It’s probably a waste of time. If he can avoid dying, he probably would. He can run away and get back to full health in mere minutes, amass a small army of charmed humanoids in mere hours, and reanimate their dying bodies constantly during a fight. I’m sure he would let himself die and go back to Hell if it meant securing a really important objective, but I assume he generally avoids pointless deaths.

He is insanely mobile, and very good at attrition. An amazing skirmisher.