Galen Walton Erso was a human male scientist, whose research focus was on crystals, and how they could be used to supply power. Erso particularly focused on Kyber Crystals, which were used to power the primary weapon of the Jedi Knights and Sith—the lightsaber. The crystals were rare in the Galaxy however, so Erso and a field team went to the planet Espinar in search of rare crystals like the Kyber crystals. During the six month expedition on Espinar, Erso's life changed forever after he fell in love with their guide, Lyra. The field team failed to find anything similar to Kyber Crystals, but Lyra and Galen left the planet together.
- Catalyst: A Rogue One Novel (First mentioned)
- Catalyst: A Rogue One Novel audiobook (Mentioned only)