Leanna is Sareth's good love interest as opposite to Xana who is his evil love interest in Dark Messiah of Might and Magic.
Leanna is a young Wizard of Stonehelm, niece to Menelag and part of the expedition to find the Skull of Shadows. She wishes to retrieve the Skull and use it to defend her city. She becomes Sareth's companion as they search for it.OffBck
Leanna is kind of Sareth's moral guide as she turns hostile if Sareth is immoral, making the game impossible to continue as "If Leanna hates you or dies then your mission is a failure.".
She is a promising mage, a determined leader and a caring person who welcomes Sareth into her uncle Menelag's mansion when Phenrig envoys Sareth to Stonehelm to deliver the Shantiri Crystal to Menelag and join his expedition to the Red Skull Island for the Skull of Shadows.
Sareth instantly gets interested in her, much to her uncle Menelag's disapproval who is aware of who Sareth truly is even as Sareth himself is unaware of himself yet.
The night after Sareth's arrival, necromancers attack Menelag's mansion, capture Leanna and interrogate Menelag until Sareth intervenes, leaving an opportunity to Menelag to kill his distracted interrogator before getting himself killed by the ghoul who was holding Leanna and who then takes the Shantiri Crystal and runs away on the city's roofs, pursued by Sareth as commanded by a grief-stricken Leanna who still remains focused enough to not forget the theft even as she cries onto her dead uncle's body.
Leanna has been fighting undeads all over the city while Sareth has been pursuing the Shantiri Crystal then once they reunite, she expresses relief and concern for him while still not forgetting to inquire if he did get the Crystal back and she is still determined to lead the expedition for the Skull of Shadows even without her uncle, relying on Sareth instead as she basically orders him around while barely doing anything herself, which Xana makes fun of, but Leanna still does more than Xana who merely stays in Sareth's body and does nothing at all, at least Leanna supports him in battle with fire balls and healing and telekinesically moves heavy objects around to open paths.
Leanna starts hitting on Sareth after they take back her boat from the necromancers who had stolen it as she invites him inside her cabin to express her feelings to him, triggering Xana's jealousy, until she gets interrupted by a mage informing her that the boat is ready to sail.
Then during the night, Sareth sees a dream in which Arantir dances with Leanna until they notice him then Arantir tells Leanna to dance with Sareth "for as long as he allows it", which she does until Sareth stabs her, much to both Leanna and Sareth's surprise while Arantir claims that she will not be Sareth's last victim.
Then the boat reaches the Red Skull Island and Leanna warns Sareth that the island is inhabited by hostile orcs and goblins then explains that they were created by wizards during a war against demons by transfusing demon blood into human bodies and leads the expedition into the island.
Inside the Shantiri ruins, she keeps sending him around while not liking staying alone behind and when Arantir arrives to catch them, she gets between him and Sareth and screams to Sareth to run away and continue the mission while Arantir captures her and expresses disappointment that "she chose the wrong side because she had potential" and Xana sarcastically says that "she is soooooo sorry about Leanna" and to forget her and run, to which Arantir answers "Yes, run, abomination, I will find you." hinting that he hears Xana as well.
Sareth discovers that Arantir didn't kill Leanna and brought her to Nar-Heresh when he invades the place and hears her angrily shout that "if she gets free then she's going to tear this place apart with her bare hands!", much to his relief, before she gets thrown down into a pit then he can either descend to rescue her or ignore her and leave her to her fate, which Xana obviously suggests.
If Sareth descends into the pit then he rescues Leanna from a giant spider which makes her so happy that she almost lets her love for him slip from her lips and which annoys Xana who didn't mind getting rid of her rival.
However, Leanna notices Sareth's demonic aura since Xana offered him her power to revive him as a demon after Arantir killed him in the Shantiri ruins and asks him to renounce his demonic power, annoying Xana who points out that Leanna is not tolerant to Sareth's nature.
Leanna stays behind in Nar-Heresh in order to close their portal and stop necromancers to pour into Stonehelm while Sareth goes in front to stop Arantir from slaughtering the city and if Sareth chooses to purify himself into the Sanctuary of Ylath in Stonehelm then he banishes Xana from his body back to Sheogh and Leanna is happy about it and accompanies him to the end however if he chooses to keep Xana then Leanna is disappointed and turns hostile, which leaves him no choice but to kill her, much to Xana's joy.
Then if Sareth chooses to seal Sheogh away forever then his father Kha-Beleth curses him "for being as weak as his mother Isabel" and promises to get his vengeance on both him and Leanna, however if Sareth chooses to free his father Kha-Beleth from his prison, much to Leanna's astonishment, then Kha-Beleth grants Leanna to his son Sareth "to do as he pleases with her", that is, if Sareth did purify himself in Stonehelm and banished Xana back to Sheogh, otherwise he killed Leanna and Xana is the one with him in the end.
And if Sareth did not rescue Leanna from the giant spider in Nar-Heresh, then she died and returns as a vengeful lich wanting to kill Sareth and get reunited with him, both in service to Arantir. However her battle is the same as any lich's battle, she even uses the generic lich voice during her battle even though she spoke with a unique lich voice before the fight.