By mastering 1 White Mage A-Ability and 1 Fencer A-Ability as a Viera. Elementalist can also lead to Summoner and Assassin, Which is my personal favorite.
If you mean the monster dragon, then get a hunter (by mastering 2 archer abilities) and capture it, or if you mean the bangaa dragoon, master 2 warrior abilities.
From what I can remember, Illusionists are mages that cast spells that can reach all enemies or allies on the field. They have a low defence, so it's a good idea to keep them holed up in a corner of...
An A-Ability is an Action ability. Action abilities are abilities that become available as actions in battle. For example, Steal Gil is an A-Ability for the Thief job class. A-Abilities are different...