2018 · ソースブック（プレイを拡張するルール／オプション）

The Frontier Companion Vol. 4

This sourcebook expands the science-fiction roleplaying setting with five new character classes: the heavy-weapon specialist Gunner, dual-pistol Gunslinger, close-combat Juggernaut, long-range Sniper, and elemental psionic Witch. It also collects new equipment and weapons, including heavy weapons, 17 pistols, 13 close-combat weapons, and 11 sniper rifles. Additional rules cover psi-crystals, rare minerals from Prometheus that enhance psionic abilities.