Adrienne is not one of original Restoration of Erathia heroes, but was introduced in the Armageddon's Blade expansion. She is not typically available in custom scenarios, unless the map-maker has enabled her.
Some may find the information in this section subjective or irrelevant.
Adrienne's specialty makes her the only hero that by default starts with an Expert secondary skill. It has no actual gameplay effect in term of that Expert Fire Magic can be removed from her starting skills by the map maker. If Fire Magic was removed and will be learned later by any means it will only be at Basic level.