The pit fiend has unlimited uses of the Fireball spell. On the surface, this looks like a really cool feature. (Fireball is one of the most popular D&D spells, and packs a really strong punch. Being able to do it unlimited times should be awesome.)

However, the pit fiend's other attacks are so strong, it doesn't seem like casting Fireball is going to be the right choice, basically ever. I'm wondering 1) do other people agree with me on this? 2) does anybody have suggestions how to set up a situation where the pit fiend can use its unlimited Fireball?

(disclaimer: collecting information for my blog dragonencounters.com)

Reasons for the Pit fiend to spam Fireball rather than start biting etc.

• Facing something that is vulnerable to/ dislikes fire, such as green slime, trolls, ice golems, etc.
• Facing three or more enemies in a tight location. You entered the hallway of fiery death!
• Ranged attackers. Standing on top of a castle blasting all the tiny folk trying to assault it.
• Facing something with a high AC but low dex save
• To start a fire - whether it is a campfire or a forest fire, fireball is the best lighter around.

Also if it's facing enemies that it can't or for some reason doesn't want to get close enough to melee or enemies that are resistant or immune to magical piercing, bludgeoning, or slashing damage but not resistant/immune to fire.

If you want the pit fiend to use fireball, give the PCs a legion of mooks (including things like conjure animals). Fireball spam isn't great against PCs, but it's good against hordes.

I don't think you're really meant to use Fireball or Hold Person or Wall of Fire spells in a fair fight, but those are mostly just for flavor because it seems like a Pit Fiend would be able to do that kind of stuff. 

Also it's nice to have some weaker options available to the DM when you want the players to feel like they are up against a giant horde of devils (which generally would be the case in the Nine Hells) but you don't want the party to get completely wrecked.  So maybe the Pit Fiend stays in the back spamming weak fireballs while letting waves of weaker devil minions get slaughtered, then the final wave is the Pit Fiend up close in melee.  It's nice to have options on the statblock

Quote from DrJawaPhD >>

I don't think you're really meant to use Fireball or Hold Person or Wall of Fire spells in a fair fight, but those are mostly just for flavor because it seems like a Pit Fiend would be able to do that kind of stuff.

I think it's more of a holdover from earlier editions when pretty much every high-level monster had innate spellcasting ability.

• Taking pot shots while commanding an army from the back line or air
• Destroying priority targets and infrastructure like supplies and siege weapons 
• Thinning the demonic hoards or decimating approaching human armies.
• Clearing space. They can come in like a meteor swooping in by surprise with a fiery explosion. 
• Mass executions of prisoners by fire. 
• Testing enemies to see if they are worth fighting.  If they can't tank a fire ball are they really worth a fight for a pit fiend?  
• Torturing immortal souls
• Burning fleeing foes too far for the fiend to fly to an hit that turn. 

If you want fire ball to be more competitive I'd recommend replacing it with delayed blast fireball it's both more flexible and more powerful so would require only 3 targets to be better than melee as opposed to 4 so is more likely to come up in combat.  It could also be an interesting mechanic to have the ticking time bomb of the fire ball.

I use it for dramatic flair. There's nothing like seeing an enemy casually drop a fireball to get the players attention and concern.

Thank you all for your advice. You've definetly given me a bunch to think about. I especially like the ideas of giving the players mooks and the idea of having it use fireball to see if the PCs are worth bothering with. 

guys i figured it out. just narrarate teh pit feind shooting fireballs out of somekind of deamon gun