Tomb of the fire-lizard Hero

1. The players are on a job for the town's mine boss: The mine shafts broke into the tomb's chambers, and since then there have been increasingly frequent and brutal attacks on miners by the savage fire-lizard tribe which lives there. Their task is simply to stop the attacks and allow mining operations to resume, by any means necessary.
2. An ancient and long-forgotten hero of the fire-lizard empire, from the glory days of their rise. The fire lizards were once honorable and brave, long before their empire bloated, stagnated, then fell to the devious machinations of Mephistopheles. The hero entombed here would be outraged and disgusted by what his people have become.
3. The deeper chambers are guarded by powerful magical traps and guardians, including fire weirds, flamethrowers, fire mephits, magma showers, and dinosaur skeletons which animate upon detecting intruders. The hero's sarcophagus is itself mounted in a giant construct which resembles a triceratops skeleton, embellished with gold, turquoise, obsidian, carnelian, and intricate patterns.
4. The upper levels are inhabited by barely-sapient pyromaniac lizard barbarians. That's the main danger. Some of the other tunnels in the mine shafts outside the tomb are den to carrion crawlers and oozes.
5. Very aztec/mesoamerican, heavily featuring reptilian, fire, and volcano/mountain motifs. Curvy serpent/lizard/flame statues contrasting with angular ziggurats and pillars.
6. It's ancient, but the advanced techniques with which it was built grant it some serious longevity. There has been very little tunnel collapse, and magma flow changes have submerged a few lower rooms while emptying the ducts in others, but things are holding up. The areas where the lizard tribe now resides are somewhat rearranged and repurposed. It's also very tastefully decorated if you consider strung-up, charred corpses and skeletons, and black horned demonic effigies, to be "tasteful."
7. The hero's sarcophagus contains the intelligent magic Macahuitl, Great-Tree-Burning