Collecting all of them though is a challenge, and the 'Fateful Heir' trophy requires it. Another disadvantage is that there are weapons in the game that approach or surpass the strength of the Royal Arms. The principal problem is that you lose a little bit of HP every time you use a Royal Arm. Royal Arms are some of the most powerful weapons in FFXV, but there are some disadvantages to using them. In fact, some Royal Arms don't fit into the pre-defined weapons categories one is a bow, and another is a throwing star. Each Royal Arm is unique, with its own stat boosts and method of play. Royal Arms originate from the past kings of Lucis, and as heir to the throne of Lucis, Noctis is the only party member that can use them. Not too far into the plot of Final Fantasy 15 you'll encounter your first Royal Arm.
