Haedron

"'Why are there so many empty rooms? And monsters? Pff.'"Haedron is the fifth NPC of Ruby Caverns to be encountered and freed. He allows the changing of dungeon generation, for more items and less enemies.

In Dungeon

Just like with Marc, after beating the game with the Good Ending, you can find a block of TNT in the Mines. Place the block on a spot to blow a wall up and free him.

In Main Area

In conversation, he says he's an engineer of some sort, and would like to update the dungeon a bit in your favor. It takes 15 rubies, quite the amount, to change a single generation. [It's hard enough.] [Green Caves!] [Blue Caves!] [Purple Caves!] [It's hard enough] will disable the current bonus generation, if any, but will not refund anything when there was one.

[Green Caves] will enable the Green generation. This will yield more Food rooms, more Treasure rooms, and less Melee enemy spawners (Zombies, Vindicators, Magma Cubes, and Husks).

[Blue Caves] will enable the Blue generation. This will yield more Blue Boxes and White Boxes, and less Hazard enemy spawners (Silverfish, Cave Spiders, Creepers, and Charged Creepers).

[Purple Caves] will enable the Purple generation. This will yield more Scroll Chests, Magic Chests, and less Ranged enemy spawners (Skeleton, Witches, Ghouls, and Blazes),

Please note the following things:
 * The beneficial generation will not interfere with Challenges or Split Mode. However, certain combinations may lead to a large amount of Golden Chests and/or Throne Rooms (the rooms that are generated if no room is selected twice in a row).
 * You may have noticed that there is no way to decrease the amount of Average enemies (Spiders, Armored Zombies, Wither Skeletons, and Large Magma Cubes).
 * These special generations reset after any failed (or successful) run, and will require another 15 Rubies to activate.