Echo World : The Martyr is a mod featuring the Martyr, a black slugcat. The campaign begins in the Subterranean, and the character has a special ability that alters lifeforms around it. However, the Martyr only has 10 cycles to complete its journey, leaving little time to sniff the roses.
*SPOILERS* The Martyr begins its journey in the Subterranean because it is a creature that has come back from ascension. The reason it comes back is to deliver a message to iterator Five Pebbles in the form of a pearl. Whether or not the Martyr is able to ascend a second time is up to the will and merit of the player.