This is a simple layout tomb complex designed either for a simple standalone adventure or as a destination along the way to something else such as retrieving a lost artifact. The legend has it that Kelroth was interred in the large octagonal room to the east, surrounded by the sacrificed bodies of his companions. Then there are two sets of sealed stone doors. In the corridor are eight more bodies of underlings below broken light sconces who sealed themselves in the tomb, while the four lieutenants of Kelroth are in the large sarcophagi in the rooms either side.
I’ve left the other rooms undetailed – they can contain treasures, or records, or religious artefacts as the scenario suggests. The dragon skeleton is purely for eye candy unless you fancy having an undead dragon burrow through the wall.