E4M9: Mausoleum (Heretic)

E4M9: Mausoleum is the secret map in The Ossuary episode of Heretic Shadow of the Serpent Riders, and can be accessed from E4M4.

Secrets

 * 1) The lava lake on the west side of the map has three branches that go to the east, each of which leads to a secret door Undead warriors inside: the further south contains a shadowsphere.