Ummm.... so. Either everyone is making it deliberately hard to find out anything about these Holy Arks of Secrecy, or it's true that nobody knows anything about them. The only google search result for "Lineage 2 Holy Ark of Secrecy" even remotely related to L2 points to a forum where someone is asking the same question, in a slightly less-concerned manner.
I found Holy Ark of Secrecy 1. It's a pretty, shiny treasure chest hidden behind some rocks, and you can talk to it. When you do, it just says something about a forboding aura surrounding it. No quest, no interaction, and it's apparently invincible. The person in the forum mentioned above found Holy Ark of Secrecy 3, which is similarly invincible and non-interactive.
I mailed NCSoft, and the response goes (something) like this:
"We can't tell you, because you suck. Go figure it out for yourself."
So that's what I'm doing, by asking everyone else :P
So, what is the Holy Ark of Secrecy??? :confused: