DrWho2010 already explain majority of things so i make the tldr and trivial info

1) Student of Baldesion is a Sharlayan Organization which their main HQ is on the Isle of val. originally on the Eastern Sea of Old Sharlayan sea, but now its near Hingashi /?
2) dead
3) Unbalanced and high concentration of Aether makes the wildlife OP. and somehow they can rip off the portal gates to the void too.
4) its called 'Arsenal' because it contains some (DANGEROUS) weapons + 'Baldesion' because its the name of the leader/Founder (Galuff) and the organization itself.
the enemies on the hallway is actually a Sharlayan guardian (Calcabrinas, Porrogos, and Biblios) so they're basically protecting the place from anykind of unknown threats.
5) a Primal, will forge anykind of 'weapon'/'item' for their master, and will posses their master/wielder too (Odin's Zantetsuken). the weapon that was stored in Baldesion Arsenal are weapons that created by Eureka.

"Whats the deal with Ascian?"
Galuff biggest concern are: Eureka can make anything . if Ascian able to control Eureka, we're doomed

"who's/when they summoned Eureka?"
we dont know yet, but posibilites are Eureka is Summoned at the 3rd Era when Allagan still exist. since its hinted for Zantetsuken were Forged at Allagan era.
but it can longer than that....

"what is Ozma and why theres a lot version of it?"
a shiny marbles that can rip the spaces and make a Blackhole.
- Proto-Ozma / Shades : Baldesion Arsenal last boss, this Ozma is created by Eureka. this is the 'Original' Ozma.
- Ozma : Weeping city of Mhach 3rd boss, this Ozma created by Mages of Mhach, trying to replicate Eurekan Ozma.
- Demi-Ozma : the mount, this ozma is created by the scholar of sharlayan. the friendliest Ozma that actually cant make a blackhole.


i havent play the game for awhile so maybe my information is semi-wrong, any correction is appreciated tho