Warlock: Warlocks are masters of spell weaving. Warlock primary spells take about Aion Gold twice as long to cast as regular spells in the game however, anytime the Warlock casts a primary spell, they can (at no cost) add in a secondary spell that will land at the same time as the primary. This allows Warlocks to mix and match pairs of spells to fit whatever situation they find themselves in.
This class is only available to Catacombs users.
Newer servers will have more low level players and less of a established community, which puts you more even with the other players. There are advantages to each one and you have to decide which you prefer.
Once you have chosen a server, you need to choose your Realm. This is a crucial choice because once you start a character in a particular realm; you cannot play a character in the other two realms on that server.
I would suggest you go through the class and zone links and the spell lists on this site and read through them carefully to decide where you want to play. Each realm is unique, with its own set of classes, races, spells, skills, items, mobs, etc.
Don't panic over the decision. Remember, you can always delete out the character and start over in a different realm if you decide you don't like the one you are in.