This is my personal fan theory/head canon for the lore of lost Galaxy. Please read and tell me what you think:

1. The Galactabeasts were from the same galaxy as Titanisaur and Captain Mutiny. After Captain Mutiny and his crew tamed and corrupted Titanisaur, one wizard/sorcerer, the most powerful in the universe, whose name was Orion, used their power to create the Quasar sabers based off the individual energy of each Galactabeasts (Hence why the ranger's helmets resemble them) and bestowed them upon five warriors to combat them.

However, Titanisaur and the space pirates were too powerful so Orion used some magic to create a wormhole which brought him and the Galactabeasts to the current galaxy. It was during this that the Rhino, Pheonix, and Shark Galactabeasts lost their powers helping the others escape, and they were left to drift in space like Deviot said.

2. After reaching the current galaxy, Orion used more of his power to seal off the Lost Galaxy and put that energy into the Galaxy Book, he then gave the book to that Guardian for safe keeping.

Unfortunately, hearing how powerful he and the Quasar Sabers are, every evil force in the universe targeted them. It was here that Orion created the Transdaggers and used them to seal away the Galactabeasts true power and was forced to send the Galactabeasts scattering across the universe for their own saftey along with the Transdaggers.

As his chosen warriors slowly got destroyed one by one, Orion created the Magna powers and created the Torozord based off those new powers and gave them to the greatest hero on the planet he had arrived on before the evil forces attacked. That warrior became the first Magna Defender.

3. Eventually, the five original Quasar Saber holders were all defeated and killed, so Orion had to leave the Magna Defender's world and sent the Quasar Sabers to a remote planet somewhere else in the galaxy (which will happen to be Mirinoi).

It was at this point Orion had exerted himself far beyond his body's limitations, so he used his final spell to dispel the rest of his powers into a single source of energy, hence the name, Lights of Orion.

He then trapped them in a small chest and sealed them in a cave on a distant planet which will eventually be revealed as Earth. After all that, Orion had used up all of his life force and passed away. The rest of the story goes the way it did in the show

I know this a lot but like i said, this is my headcannon for the lore and history of Lost Galaxy. It's obviously not the exact truth but then again, they never explained where the Galactabeasts or the Galaxy powers came from so whatever. This is based on lost Galaxy and not Gingaman.