- "No one's sure what it is, or where it came from, or what it wants."
- —Kiazuki's opening monologue in A Moonflower is Born
- The Big Bad is the main antagonist of Hanazuki: Full of Treasures. It is a shapeless and pitch-black void that envelopes moons, devouring almost any organic matter from their surfaces. Its origins are unknown, and its purpose seems to be the total annihilation of the galaxy, if not the universe.
In the first episode, the Big Bad makes it's first appearance where it's shown destroying an unknown moon and later in the same episode where it's being worn off by the force of Hanazuki's treasure tree. Later, in episodes (Friend or Foe, Forgive and Forget, Brain in a Cave) the Big Bad fails while devouring Hanazuki's moon up until Hanazuki and Kiazuki's Treasure Trees manage to stop it as they are the most effective deterrents to the Big Bad, but other moons who have no treasure trees have relied on other means to protect themselves from it, such as the Unicorns using their magic to power a dome to keep the Big Bad away (though it was mentioned that the dome functionality wasn’t actually proven).
- A Moonflower is Born (debut)
- Friend or Foe
- Forgive and Forget
- Brain in a Cave
- True Colors
- Damage Control (mentioned)
- Recovery (mentioned)
- The Transplant
- Big Bad Sickness
- Even though the Big Bad is referred to with it/it's pronouns in the show, the mobile app refers to the Big Bad with he/him pronouns
- The Big Bad seems capable of reacting to the outside stimulus, but it's unclear if the Big Bad has any kind of consciousness.
|Moonflowers||Hanazuki • Kiazuki • Kiyoshi • Maroshi • Miyumi|
|Hemkas||Red Hemka • Orange Hemka • Yellow Hemka • Lime Green Hemka • Green Hemka • Light Blue Hemka • Blue Hemka • Purple Hemka • Lavender Hemka • Pink Hemka • Raspberry Hemka • Emerald Hemka|
|Unicorns||Sleepy Unicorn • Twisted Unicorn|
|Other Characters||Little Dreamer • Zikoro • Doughy Bunington • Dazzlessence Jones • Dazzlessence Jackson • Chicken Plant • Baby Chicken Plant • Junior • Mirror Plant • Axo • Enormous Coal • Mini Coals • Depriva • Rainbow Hemka • Mountains • Pyramid With a Face • Mouth Portals|
|Villains||Big Bad • Basil Ganglia • Mazzadrils • Moon Widow|