Where does this DRK sword come from?

[Bacent]

Also don't forget to mention the fact that when you finish the relic, you can buy a level 1 version of every stage of the relic weapon to glamour, including a matte version of the final weapon with no glow.

[Jojoya]

As an aside, I'd love to not have to ask the community these kinds of questions, but you don't seem to have a "WoWhead equivalent" (which has pros and cons), unless I missed that.

Nothing quite on the level of WoWHead but we do have sites like

https://ffxiv.eorzeacollection.com/ (glamours)
https://garlandtools.org (item database/gathering timers)
https://ffxiv.consolegameswiki.com/wiki/FF14_Wiki (general game information)

Overall, the fansites for FFXIV tend to be more focused on certain topics than broadscope like WoWhead.

Don't be afraid to ask around in the community when you're looking for certain types of information. Someone can usually direct you to a website, Discord or content creator channel with the information you want. Eventually, you'll get a good collection of references that will reduce the need to ask others.