Actually, they're supposed to mean something in latin, i'll search that and write it down in the end of the post.
What he meant, is that you have to pick a realm when you start. The game is like that; There's 3 realms that are in competition to each other. each realm has it's own established area that's behing closed walls, and the area in the center is up for grabs
it's the pvp area, where people fight against each other if they are from different realms, and fight to take over enemy forts (or take back your own).
There's pvp also in the arena that's inside the safe zone of each realm (behind the walls).
Check out the info on the site, it should help you a lot.
PS1: Yeah, the game is VERY VERY good, and has even better potential once its 100% complete (you'll find out more about this in time, lots of stuff is being planned and implemented). You are really gonna enjoy playing it. Its also free, did i mention that?
PS2: the names mean something afterall:
Ignis means fire in latin
Alsius means cool/cold in latin
(it could probably mean something in latin too, since the other two do)