#timepools

Traveller's Crystals, also informally referred to as Timestones, are the creations of the Time God Manticore and his children.

The crystals always start out blue, but the more they're used, they slowly change color from blue to pink to red to grey. Red and pink can be recharged back up to blue if left unused, but grey crystals are dead and useless, hence them being the ones found around the Timepools. The pools use a lot of magic, so the only crystals they produce are dead.

Traveller's Crystals/Timestones, as their name implies, allow the user to travel through time & space via portals they generate when touched with the intent to travel. Blue crystals are capable of hopping Universes, Pink through Timelines, and Red only allows travel through the universe/timeline the user is currently in, though still allows time-hopping in general.

The crystals are not to be given out to Mortals without careful consideration and Manticore's express permission. They are precious and supremely dangerous in the wrong hands, so any Mortals who wield them must be vetoed and trusted. The only ones who naturally have the crystals as part of their bodies are those who are related to Manticore, like the Time Children and Ishtar. Otherwise, a good handful of select Mortals across the multiverse wear them as accessories.

The crystals can be destroyed, but the fragments will be useless due to the "liquid" (more accurately, condensed magic) inside evaporating on contact with anything outside the crystal. The fragments can be welded back together and refilled with magic by Manticore and the Time Children, but only by them, and only if it's done quickly before the fragments turn grey. There is an infinite number of crystals, since Manticore and the Time Children can always create more no matter what.

Grey crystals can still technically generate "portals", but they don't lead anywhere and are more of magical shields, platforms, or discs. Grey portals can only be summoned by the Time Child assigned to them, Scorpion, and Manticore. No one besides them in possession of a grey crystal can do anything even resembling portals, so many deem them useless beyond aesthetic appeal.

However, grey crystals do have an actual use. At their center, they generate a small, circular, green gem. This is called a Greenscreen Stone, and functions as illusionary magic, allowing the wearer of one to tap it and cloak themselves so thoroughly it resembles shapeshifting. Extracting Greenscreen Stones from grey crystals is an extremely delicate process, due to these crystals being far more fragile than blue/pink/red, and the stones sharing that trait.

If a Traveller's Crystal is broken neatly in half and sealed without allowing the magic inside to spill out, then you create Twin Crystals. These allow the wielders to switch places with each other by tapping their half, or summon the other to their location by holding their half with intent to do so. The tapping causes the other's half to flash with warning, and holding the crystal after already summoning just warps the other back to where they were. Importantly, these function across time, space, Timelines, and Universes, allowing for (as some would put it) fun crossover shenanigans.

The most known users of Twin Crystals are the Monkey D Luffy and Shirakumo Oboro from their respective "SunCloud" AUs, but they certainly aren't the only ones.

This has been your introduction to Traveller's Crystals. As implied at the top, I have no problem with anyone using these or something similar, so long as if they're named & explained like this, I am credited. I will eventually get around to making a post explaining Manticore & the Time Children, but that's for another day. This covers all I wanted to when it comes to the crystals, but I'll probably realize I forgot something and circle back to add it.