A Hybrid World is a glitch state where the screen Link is in belongs to a different world than what his current World Variable is set to. This conflict has a number of important consequences for glitched speedruns.
Link's world is controlled by the value at memory address
$0FFF, which we'll call the World Variable. In normal gameplay, the value at this address will always be in agreement with where Link is. However, through various glitched means, we can get Link to physically be on a screen belonging to the opposite world that his World Variable is set to. If he's on Dark World screen but the World Variable is set to Light World, we call this being in Fake Dark World. If he's on a Light World screen but the World Variable is set to Dark World, we call this being in Fake Light World.
Methods for Being in a Hybrid World
There are a number of different ways you can be in a Hybrid World state:
- Clipping, using Transition Corruptions, or EGing to travel from a cave/dungeon room in one world to a cave/dungeon room in the opposite world. Because all indoor rooms in the game share the same map, you can, for example, glitch from a Light World cave into a Dark World dungeon. Because Link never warped, his World Variable still thinks of him as being in Light World even though he's in a Dark World area. An example of this is Kiki Skip.
- Dying in a Dark World dungeon prior to defeating Agahnim1. When Link dies in the Dark World before defeating Agahnim1, he is immediately put in Light World. The game does this because you can theoretically die on Dark World Death Mountain before fighting Agahnim, and if the game treated this normally, we'd be placed on the Pyramid for a massive sequence break. Through using glitches, we can easily access the entire Dark World before defeating Agahnim1. Dying on the Overworld will simply place Link in the Light World and give the player the selection of Light World spawn points, but if Link dies in a Dark World dungeon, he'll be placed back at the entrance to the dungeon but with the World Variable switched to Light World, thus being in Fake Dark World.
- Fake Fluting while on the Dark World Overworld. The flute is never supposed to be used in the Dark World, but we can do it using a Fake Flute. The screen the bird takes us to will be a Light World Overworld screen, but because we never warped at any point, the World Variable still considers Link to be in the Dark World.
Effects of Hybrid Worlds
Hybrid World states have a few significant consequences, some of which help the player and make certain glitch speedrun routes possible. But there are also consequences with potentially dire effects the player may need to pay attention to.
- In the Fake Dark World, we are Link, even if we don't have the Moon Pearl. This is one of the most beneficial consequences of Hybrid Worlds, as in RMG and MG Speedrun routes, it can be faster to do some Dark World content before collecting the Moon Pearl.
- While on a Hybrid World Overworld screen, all the normal NPCs and underworld entrances on that screen will be there as expected, but as soon as you trigger an Overworld transition, the game will load the proper world based on what the World Variable is set to. So for example, if we're in Village of Outcasts in Fake Dark World and we transition south, the screen with the Library will load, NOT the screen with the Frog and the house with the shooting minigame. You'd then be in just full true Light World. This can be good or bad depending on the context. If the player wants to be in the world the World Variable is set to, it can save warp time to just transition, but if the player wants to stay in the world opposite the World Variable, transitioning can lose a lot of time. Especially if the player transitions to the Light World when they want to be in the Dark World, since now you'll need to find a way to warp back (and Mirror won't do it).