A-Photon Reactor: An A-photon reactor is a device which takes seven souls gold photon particles through the process of collection, transformation (into A-photons), and extraction of energy from decomposition.

A-photon crystals come from the refinement of photon particles. When exposed to specific vibrations, refined A-photon crystals will begin to irradiate, initializing a chain-reaction decomposition.

An A-photon reactor is a device which contains and governs this continual reaction. It can also increase the reaction efficiency through both positive and negative acceleration in vibrations, thus intensifying the energy discharged from crystal decomposition.

Modern science has only been able to make A-photon reactors fairly large in size. That is one reason their use is not as widespread as that of standard photon reactors.

Shield Line System: In Phantasy Star Universe, there are no shields or types of armor to equip. Players are able to freely change their outfits without having to worry about the outfit's effect on their defensive power. So, exactly how does one improve their defense?

A layer of photons stretches over sections of the surface of all bodies. If something strikes at or collides with these photons, they will react in relation to the force of impact by collecting in the affected area, thus providing protection for the body. This is called the Shield Line System.