FFXIV The Diamond Weapon is the final boss of the Ruby Weapon trial, and it is one of the most difficult fights in the game. Here is an in-depth guide on how to beat this trial.   Before engaging the boss, make sure your party is prepared. A typical setup would involve two tanks and a single healer, with the rest of the party made up of DPS. Make sure everyone is aware of the mechanics of the fight and has their own personal mitigation ready. 

The first mechanic you will encounter is Diamond Rain. This is a very hard-hitting raid-wide attack, so make sure your healer is prepared with shields and heals. After Diamond Rain, the boss will cast Adamant Purge. This is the most deadly mechanic in the fight, but once you get it down it is fairly easy. The boss will open large purple claws on one side of his body. If you are on the platform on this side, take a teleporter to the other side. This will be followed by either a stacking mechanic or a spread mechanic. If it is a spread, the boss's shoulders will open, revealing glowing rocket launchers. Spread a reasonable distance from each other and be extra cautious on your first run. If it is a stack, the boss will open a large glowing cannon on his chest. Stack in the middle of the platform. 

The next mechanic is Photon Burst. The boss will mark the top two players on the enmity list with flare markers. These can be moved to the corners of the platform without going to the other platform. Once the flares detonate, the boss will attack these players with auto attacks in the form of lasers. These will hit any player standing behind the primary target. The players with the flares should stay on the outside corners until the autos are done.

These mechanics will repeat until the boss casts Code Key 11 Stigma. The boss will then disappear from the arena and players will be marked with tethers. There will be a knockback circle at one end of your platform. If your tether is pink, you want to be knocked to the other side. Stand at either three o'clock or nine o'clock just outside the circle, depending on which way you need to get knocked. Players with a purple tether will stand at six o'clock and be knocked along the platform they are on. If a pink tether stays on the platform or a purple tether goes across, the player will die as their tether was not stretched far enough. 

Once all players land, the boss will return and mark one platform with a platform-wide AOE. Any players on this platform will need to take a teleporter to the other side. After this, the boss will then drop onto the platform and cast Outrage, which is a raid-wide attack. It only hits for about a quarter of the DPS's health but it may be worth mitigating this if the fight is going on for too long. Most groups with decent DPS can kill him in this phase.

If the boss is not killed in this window, it will cast Arits. This is a hard-hitting tank buster. If it casts this, it is best to wipe and focus on cleaning up previous phases.

The Diamond Weapon drops a random weapon and weapon coffer, as well as a chance to drop a Diamond Quiver, Trumpet, FFXIV Gil and Diamond Plating. The Diamond Plating currently does not have a craftable weapon, so keep an eye out for it. With this guide, you should be able to defeat the Diamond Weapon and earn the rewards it drops.