I really, honestly, can't believe I'm about to post this... but we're already banging our collective heads against the wall, right? Right? >_>
Okay, the only reason I post this is under the assumption that SE really honestly hopes that we're clever enough to figure this out given the "clues" they've helpfully littered around the game world.
AV talks about being freed by the chains placed on him... who else has chains? I hear that Promathia dude does.

Originally Posted by
The otherwiki's description of Promathia's first form
# Chains of Apathy: targets Humes only. No effect due to the Light of Vahzl
# Chains of Arrogance: targets Elvaan only. No effect due to the Light of Dem
# Chains of Cowardice: targets Tarutaru only. No effect due to the Light of Holla
# Chains of Envy: targets Mithra only. No effect due to the Light of Mea
# Chains of Rage: targets Galka only. No effect due to the Light of Al'Taieu
Obviously the dev video is showing us something with the 2 hours and the nuking with the day's element and all that jazz, we just don't know how it all ties together. I also note that there's at least one member of every race in the dev video. Could it be possible that when a member of a particular race reacts with their 2 hour it places the corresponding chain on AV? Sounds unlikely, but I don't know the race breakdown of any of the linkshells that have tried this, and I don't know if anyone has coincidentally/accidentally done anything like this at this point.
Anyway it's easy enough to test and prove/disprove at least.