Heya! So... this subject gets brought up a lot, but... Herklaedi, the infamous suit of armor acquired by trading in 5 Odin's Mantles.
I was thinking. Now that we have a system like Desynthesis in place where one item can turn into multiple items, I am curious as to whether or not it would be possible to split Herklaedi into its individual parts somehow. Maybe have a system where you can hand in a Herklaedi set to an NPC for a special quest similar to the Lv45 Job Quests.
As part of the quest (If you want to call it something witty, maybe something like "Trials of Herklaedi", referencing the Trials of Hercules from Roman Mythology), players learn more about the Dark Divinity and, as they do so, stumble upon ancient pieces of armor: A chest slot piece, a hand slot piece, a legs slot piece, and a feet slot piece, each in different places. Then the player takes the Herklaedi and the ancient pieces of armor to Gerolt, who will then use his mastery of the forge to infuse the power of Herklaedi into each individual piece, destroying the original Herklaedi in the process, and these pieces of armor could be granted depending on the current Job of the player, so any Job could equip a variant of the Herklaedi gear (other than PLD/WARs, who would get the genuine article), and the quest could be repeated so long as the player has a Herklaedi in their inventory.
This quest could also unlock a special quest (Maybe call it something like "A Dark Divinity Reborn" or something), where the player, after getting a full set of Herklaedi gear, starts wondering about the Hjalmr and the Zantetsuken (The Hjalmr being required to start this quest), and has to go onto the second part of this quest where they find out the true backstory between Odin and Urth and, by the end of this quest, get a "Demimateria of the Dark Divinity", which would be used to give to Gerolt (along with a specific head slot item and the Hjalmr) to get a special Hjalmr helm that would fit a Tank, DoW, or DoM.
It could also unlock a special battle against Odin, where the spirit of Urth comes to your aid to severely weaken the Elder Primal (Justifying an 8-man fight against an enemy that is normally fought with 60 people or more), where you could be awarded Zantetsuken-inspired weapons and maybe even a proper Sleipnir mount.
This is all just one big, random idea. Take it or leave it. I just had to get it out of my system.