Jaania or Lady Jaania is a woman.
Often she would be obvlious when Warlic and Alexander would fight over her, such as when the two wrecked the classroom trying to gather books for her, or one of Alexander's pranks, where she often saw the result of the prank.
When Warlic and Alex (Xan) decided to fight one more time, Jaania then attempted to break the two of them up, by jumping right into the middle of their crossfire, which ended in Warlic's magic-reflection spell returning Alex's ice spell into Jaania, which encased her inside a crystal for all of this time...
Jaania was inside the crystal, many years passed.
During the events of Book 2, it was brought to reason that Jaania's own release from the same ice-crystal could potentially help in trying to bring Archmage Warlic back to normal.
It is possible that during 5 years, she began an organisation called The Rose, which tried to exterminate magic from Lore.
In Book 3, she is called 'Lady Jaania' by all of the Rose Soldiers so it is possible she has a very high ranking within the Rose organization itself.