These cultists are somewhat more coordinated than their allies he's fought previously! The non-pentagram-wearing cleric can channel negative without catching all her allies in it, and they're capable of basic strategic maneuvers like "everyone gang up on the squishy tiefling who thinks he's too good for us" if not complicated ones like "recognize whether the tiefling is in fact the most important target."

No, if he dies now he'll never get back at the asshole who sold them out—

Meh, once he's down the cultists who are standing will focus their efforts elsewhere.

He should probably have done a second buff before wading into melee. ...He's doing more damage than Seelah is and his spells have more option value than does a Lay On Hands. "Ser, please get him up again," he says, moving to cover this maneuver.

She bends down and heals him.

Huh. Apparently there are some advantages to travelling with goody-two-shoes paladin types.

Seems like a good time to stab him again—

What if, instead, she skewers that brute's hand?

Then he will be impaired in stabbing!

When everyone but the guy with the pentagram is down, he holds up a hand. "Wait! I surrender!"

"Get rid of the pentagram," Blai orders.

He reaches for it, as if to remove it from his neck.

...Instead of actually removing it, though, he uses the brief pause in people stabbing him to channel negative energy at everyone within reach.

Yeah, predictable. Blai swats him again.

He goes down.

Woljif is down again. She lays on hands, and — huh, she feels kind of different—

If Blai gets within ten feet of her he may notice himself becoming mysteriously fearless.

She starts finishing off the downed cultists.

blai.exe is not responding

"Is something wrong, boss?"

"Hey, you can't go dying on us too, that's my thing!"

Eventually, like a window blowing open because nobody secured it against this outcome but not because anyone pushed it, he figures out what must have happened.

"Ser Seelah. Please stop that."

"Uh, I'm happy to, but what exactly do you want me to stop?"

"Your aura has come in. It disagrees with me."

Oh, is that what that is? 

It takes her a few moments, but she can eventually figure out how to stop projecting fearlessness at him.

"Sorry! I didn't realize that was something people could have problems with."

He shakes himself slightly, considers scolding Camellia but then decides that they can't transport these cultists any more than they can the library ones and the survivor in the library is at least relatively sheltered from wandering dretches, and nods. "It's also news to me, but here we are." He collects and destroys the unholy symbols.

"Why did that one's symbol look different from the others, anyway? What do stars have to do with Baphomet?"

"Baphomet is a particular enemy of Asmodeus and allows the use of a symbol matching His so that cultists can infiltrate Asmodeans more effectively."