Against the cult: the Forest Ruin (1.5)

Standing over Joseph's body, Aanbo readies an attack on anyone who approaches. Now that Xana has disrupted the ritual, all that remains of the undead priests is ancient dust that swirls around the monk's feet as he surveys the room warily.
Theran swings his shillelagh at K but each hit is a glancing blow that doesn't seem to slow the wizened figure!
Albertus runs up and attacks K, but the dead thing keeps sidestepping the fierce swings!
But Kragga's staff manages to catch K in the jaw as he dodges back, snapping his mandible to the side for 4 bludgeoning damage!
Atop the table, Xana supervises the party with calls of "Ooh, better luck next time!" and "Good shot! It seems like you've learned a lot from my training!"
Joseph drools.
With the ritual magic disrupted, K cackles and sobs with relief, disengages from the combatants, and flees.
But his doom awaits him in the doorway. Stepping forward, Ogbar brings his axe down, cleaving into K for 11 slashing. K collapses, inanimate.

There are no apparent enemies or immediate threats. Each PC gains 85 XP!What do you want to do now?

At last! Hooray! From the Rules thread:So at this point, those of you who are gaining a level need to decide:
1) Is my PC going to gain a level in the class they already have, or a different one?
If the answer is the same class, then you also need to declare in the Character Creation forum whether you are rolling for HP, or just taking the "average." Then, if rolling, you can also post that roll.
If the answer is "a different class," then your PC's HP gain will wait (along with all other new abilities) until you return to town to spend time with the new class trainer.

Here I have to admit that I haven't looked at the characters with an eye to multiclassing, so I don't know whether it's even an option for all of our PCs (in terms of ability score prerequisites).

Ogbar hacks up the body of K, but there are no other fallen enemy bodies to dismember.
Albertus looks at the scattered remains of the ritual implements - the skulls, the candles, an impractical knife, a large silver bowl, a number of wooden pegs, some dried twigs, and the black tablecloth - and doesn't really know much about it other than this ritual was definitely the evil that he was sensing downstairs.
Kragga examines the same materials and is able to put a name to the abomination: Kyuss, the god of evil and undeath. The hairs in his body rise up in horripilation as Kragga considers the nature of the dark ritual. Obviously, he experienced the results of the foul magic that kept the murdered priests "alive" for centuries, but being this close to the elements - particularly the candles and skulls - gives a visceral sense of residual foulness.
But as any literate PC who wishes to looks around the room now that the immediate threat has ended, they can all see and discern the following:As mentioned previously, the room is filled with carvings of Pae. It was clearly designed and dedicated to this god of light. But this sanctum has been mutilated, defaced, and despoiled by Kaufra, the final enemy you faced ("K," whose body is being dismembered by Ogbar). Scrawled in among the sacrilegious and profane graffiti are mad scrawls in many languages, which can be interpreted to tell Kaufra's sad, mad story. Kaufra was a devoted and good Herald of Pae, but when he prayed to Pae, a little voice of doubt spoke to him. Why wait centuries, it said ("Why wait centuries?" "Reward now!" and "Take your prize!" are scrawled on the wall in a very different, inhuman hand), when you could have an earthly reward now? This thought came to dominate Kaufra's waking life, drowning out his devotions. While the other Heralds were committing themselves to Pae, Kaufra came to believe that he deserved a reward for all the earthly sacrifices he had made, and he invited more of these intrusive thoughts in. By the time he came to realize that the voice came from an external source, he was too far in its thrall. By the time he realized it was Kyuss, he had already agreed to the plan. When the others began their sleep, Kaufra only pretended to partake. Then he followed them into their rooms and slit their throats while they slept. Kyuss filled him with power for this sacrifice, but the evil power did not protect him from his own carelessness, and he was caught by one of the Order's own traps: pierced and killed by spikes on the stairs.

Kyuss was not finished with Kaufra, however, and kept him alive and in the agony of his wounds to complete the ritual he had started, which would allow Kyuss to puppet the murdered servants of Pae in twisted mockeries of their original zeal ("So shall the servants of the light serve the darkness forever!" reads the scrawled text written in the inhuman hand on the wall).

All this confirms Albertus' surmise, explaining why the Heralds of Pae were dead, animated, and hostile, and it does say something about the Heralds "going to sleep," but it doesn't answer the question of why the Heralds were asleep, or how to awaken Devek. Those answers may lie elsewhere in this ruin.