The second key is found by defeating the ogres!
Belflin, Silas, and Auroleva delve into the Underdark, looking for the temple of Belphegor, the evil god of fire.
On the first day, they meet some Gnolls, but using sign language the two groups pass each other. During the night, the gnolls come back. The party feigns sleeping, and the gnolls decide to attack! The fourteen gnolls did not last long and a chest loaded with 1300 gp was discovered. Some sort of tribute to be paid, maybe?
On the second day, a wraith was fought and bested, and a group of Crushed Skull orcs was met later that day. One of the orcs knew Giant and gave Belflin directions to the ogre caves. The party followed the directions, got overtaken by the orcs by nightfall, but again nothing happened.
On the third day, the party reached a big cave and discovered a red dragon called Thuskamasker in an abandoned Belphegor temple. The dragon graciously agreed to a gift of 1300 gp in a wooden chest and let Belflin go.
The party also found a secret door with an Infernal inscription but did not investigate.
And the party got into a fight with some ogres. Their surviving leader Klusko offered to find a hexagonal gem for 1000 gp after all but two of his clan were killed. Belflin, growing suspicious, decided to search the premise and discovered the very key they were looking for in the ogre’s treasure chest.
Hurray! 
The party also befriended a lonesome & lost hobgoblin and finally arranged for him to become Crus’ servant.
Challenges overcome: thirteen gnolls CR 1, one wraith CR 5, ten ogres CR 3, Klusko CR 7, hobgoblin CR 1
| Corian | 36855 (Sor-9) | Belflin | 32996 + 3066 = 36062 (Rng-9) | Silas | 28919 + 3066 = 31985 (Cle-8) | Auroleva | 28872 + 3066 = 31938 (Drd-4/Clr-4) | Karamutenga | 30577 (Brb-8) | Flax | 11910 (Rog-5) |