There are 13 Royal Arms Locations in Final Fantasy XV. Finding all 13 unlocks the "Faithful Heir" trophy / achievement.
Each Royal Arm has unique attack patterns and stat boosts. They can be used in combat by Noctis. They are more powerful than normal weapons but using them depletes your own health. Even if you don't want to use these weapons you should equip them for the stat boosts they provide. Furthermore, the Royal Arms bypass all enemy resistances and always deal full damage (no enemies are resistant to them).
The first 7 Royal Arms are automatic / unmissable story unlocks. You get them automatically during main quests. The remaining 6 Royal Arms are from dungeons and Royal Tombs which you must find on your own. None of them are missable! There is free roam after finishing the story and you can go back everywhere. The dungeons are fairly difficult, one of them being for level 55+. If you want you can do them before leaving for chapter 9 but it will be very difficult. I highly recommend you finish the story first to get stronger. Remember you can switch to easy difficulty in the game options at any time (in easy mode you cannot die).
#1 - Sword of the Wise - 0:05
#2 - Axe of the Conqueror - 0:58
#3 - Swords of the Wanderer - 2:08
#4 - Blade of the Mystic - 3:26
#5 - Katana of the Warrior - 4:13
#6 - Trident of the Oracle - 5:29
#7 - Sword of the Father - 6:21
#8 - Bow of the Clever - 7:20
#9 - Sword of the Tall - 9:39
#10 - Shield of the Just - 12:09
#11 - Scepter of the Pious - 13:27
#12 - Mace of the Fierce - 14:32
#13 - Star of the Rogue - 16:13
Full Trophy Guide & Roadmap:http://www.powerpyx.com/fin...
All Final Fantasy XV Trophies & Achievements:
The World Wanderer
Collected all trophies.
Insomnia's Waking Nightmare
Completed the Prologue.
Completed Chapter 1.
No Turning Back
Completed Chapter 2.
The Open World
Completed Chapter 3.
Completed Chapter 4.
Completed Chapter 5.
A Way Forward
Completed Chapter 6.
Party of Three
Completed Chapter 7.
Completed Chapter 8.
Completed Chapter 9.
The Heart of a King
Completed Chapter 10.
In the Dark
Completed Chapter 11.
End of Days
Completed Chapter 12.
Completed Chapter 13.
Completed Chapter 14.
Defeated Ifrit on Normal difficulty.
Drove the Regalia.
Rode a Chocobo.
Flew the Regalia Type-F.
Equipped four weapon slots.
Collected thirteen royal arms.
Learned first ability.
Activated 20 ability nodes.
Activated 50 ability nodes.
Improved fishing level for the first time.
Improved survival level for the first time.
Improved photography level for the first time.
Improved cooking level for the first time.
Reached maximum fishing level.
Reached maximum survival level.
Reached maximum photography level.
Reached maximum cooking level.
Just Hangin' Around
Performed first point-warp suspension.
Issued first ally command.
Performed first blindside link.
Noct You Like a Hurricane
Initiated first link-strike after parrying an attack.
The Power of Kings
Called forth the Armiger for the first time.
Crafted a spell for the first time.
Used magic for the first time.
Summoned one of the Six for the first time.
High Five for Justice!
Played JUSTICE MONSTERS FIVE for the first time.
Caught an image of Gentiana in a photo.
Spinning a Yarn I
Completed first sidequest.
Spinning a Yarn II
Completed 5 sidequests.
Spinning a Yarn III
Completed 10 sidequests.
Spinning a Yarn IV
Completed 20 sidequests.
Spinning a Yarn V
Completed 40 sidequests.
Weaving a Tapestry
Completed 80 sidequests.
My First Hunt
Completed first hunt.
Defeated the adamantoise.