These are all a bit of "small mysteries" that I felt weren't big enough or important enough (especially with 10 years on the belt) to merit their own thread so I'm tossing them all together here:
Who built the giant statues in the Crystal Desert? Were they made by Ascalonians, who had similar statues in their crypts, or another group (the Seekers?)?
Speaking of whom, who were the Seekers mentioned in Seeker's Passage?
What is the origin of Kanaxai and the Oni? It’s never officially confirmed, though NPCs do hint that the Outcasts driven insane by Kanaxai become Oni. Further, Kanaxai is often related to a “Nightmare Realm” in some descriptions of The Deep (such as from the Prima Guide); Nightmare Realm is an alternative name for the Realm of Torment in Nightfall; is Kanaxai a demon from the Realm of Torment? If so, how did he get to Cantha?
Now that the White Mantle/Mursaat plot seems to have ended, what was the story of the seer in Zinn’s laboratory during War in Kryta? It was ignored because of typical "potential spoilers of future plots" but never got touched upon (directly at least).
Can we get confirmation on Evennia’s fate? Is she the Shining Blade mentioned in Caudecus’ letters, and was she truly hanged by Adelbern?
Who was the mysterious stranger that commissioned Zinn to build R.O.X., and subsequnetly forced the building of N.O.X. and P.O.X. Flashpoint dialogue hints that it could have been Palawa Joko - was it? If so, what did Joko seek to gain from assaulting Kryta and Cantha at that time? And if not, who?
Any fun tidbits you feel like sharing about development during GW1, or hidden lore that was never found? What’s your favorite part of GW1?