Dons

In Let it Die there are currently 4 main Bosses - one for every 10 floors.

On defeating each boss you will gain a Large Stamp for your Stamp Rally and a photo for your Memories in your Underworld Rolodex.

After defeating all 4 bosses you will have effectively completed the main story and will now have access to post-game content, such as Grade 6 fighters and new decals like Treasure Hunter and Giant Killer, as well as a new area beyond the 40th floor, which you can only enter with 5 items (7 with an Express Pass), and the only enemies are Haters.

As of 11/28/2018, any of these Bosses have a chance of spawning on the 100 floor and every 5th floor there after in the never-ending Tengoku. These variations are faster and stronger, and they may use new moves as well as rarer moves they normally wont use before being low on health, which can catch you off guard.