Ruin II (Ruinra in the Japanese version) is a spell and a stronger version of the Ruin spell. It is available to Arcanist at level 38. Ruin II deals unaspected damage with a potency of 100, and has no casting time. The spell can only be used by Arcanists, Scholars, and Summoners.
In addition, the ability can also be used by Tristan Nightflicker during his boss fight in the "Primal Burdens" quest.
Ruinra I-III are magic attacks available only to Morrow to use. The spells can only be learned from the Ruinra version of the Cait Sith signet. All Ruinra spells deal non-elemental magic damage to all enemies and cost 29 MP to use.
In the original free-to-play versions, Ruinra I-III could be used by any party member equipped with the Ruinra-type Cait Sith signet. Each version of the spell dealt more damage depending on the summon's rank and had increased MP costs.