This actually caused an unfortunate gaming night. The regular group hadn't gotten together in a while so three of the six (Brian, Casey, and Doug) decide to track down Raxnar the Unborn (the anti-paladin of Asmodeus) and put an end to him.
The bugbear Raxnar was lvl 7 and they were only fourth level. They were upwind of Raxnar and had goblin scouts, so he knew they were coming. Raxnar invited them into camp for a parley. They came on in and I started my timer.
After 15 minutes IRL, I said, "Okay, I get to make Raxnar's Intimidate check now." Raxnar is built to do that; Casey & Doug fail their checks and are now 'helpful' for the duration. Brian, the paladin, is immune so he, of course, doesn't stand down.
I tried to encourage him to look to his comrades but he was having none of it. They managed to kill Raxnar, but his minions killed Casey and captured Doug & Brian. The shaman used Brian's still beating paladin heart to bring Raxnar back to life.
I knew Raxnar was too tough for just three, but Brian Immune To Fear sealed their fates.
At 3rd level, an antipaladin radiates a palpably daunting aura that causes all enemies within 10 feet to take a –4 penalty on saving throws against fear effects. Creatures that are normally immune to fear lose that immunity while within 10 feet of an antipaladin with this ability. This ability functions only while the antipaladin remains conscious, not if he is unconscious or dead.