[@Lyla]

tl;dr
Yea, she had good intentions for necromancy and she had a bit of pride to go along with that when she left home to prove a point. She grew up normal and well adjusted except for that one obsession. Dagger takes advantage of her, she goes off the deep end and becomes more apathetic and crueler during the war. It's only when she is alone on some unknown land does she feel repentant for her actions. 

Long Post

Her intentions were initially to prove her father's words that nature of magic does not care for morality such as good and evil and that its usage depends on its user. In addition, she also found it strange and unfair that for a nation of magicians that touted a lassiez faire attitude regarding magical studies, necromancy was the one school that was restricted. It looked hypocritical to her and she felt her potential was stifled because she wasn't given a choice insomuch as to look at it.

Thus her initial curiosity with necromancy became a full blown obssession as the Council continued to deny her access to the restricted archives. Whether the Council was right to deny her given what has transpired in the war or if they had just been a little more open and taught her in a more controlled environment to satiate her curiosity is in the air, who knows? What does happen as a result is that Al'nehak begins to disregard the Council as fools and old farts who cling on to old traditions. Combined with her father's words, it's clear she feels that change is needed and what better way to do that than to prove that she has become versed in necromancy and use it for good?

However noble her intentions for necromancy were, they became twisted when she met the sentient dagger. Remember, she was initially skeptical of the dagger's word initially and she was ready to go home, unnerved by the strangeness that has taken over the Eastern Kingdoms. When the dagger was actually true to its word and she found in her hands a tome about necromancy, caution was basically flung to the wind and she became more susceptible to the daggers more morally grey and then outright black "suggestions" over time. She had reason to trust it. After all, it lead her to her heart's desire.

By the time she went to rescue the city of Pila, she was convinced by the dagger that she would be hailed as a hero though there was a small part of her that wondered if what she was correct in her course of action. Instead when the battle was finally over, she was disowned by her father and her own countrymen declared her a traitor for breaking an ironclad rule (the decree was issued by the hated Council).

This broke her spirit and she lashed out at what she saw as a huge misunderstanding on their part, causing her to be more callous and aggressive. However, she still had love for her home and family yet by this point, her thinking and logic had been thoroughly screwed over and she believed she could redeem herself by slaughtering everyone on the other side. It certainly did not help that the dagger was always pushing the right buttons for the wrong reasons.

Thus her methods became more cruel and callous. Her ability to empathize with the living, weakened over the many years, becomes non-existent from spending so much time with the dead and communing with the dagger. The dead became her new family. The dagger moreso. Eventually, she concludes that if they don't accept her now, they will have no choice but to accept her when they are her thralls.

After her defeat, she regains much of her senses back over time when she loses the dagger. She is remorseful for her actions and unhappy that she has caused so much death but she feels it was worth the sacrifice learning about necromancy. With no one to talk to besides herself and plenty of time to reflect on her actions, it becomes too much for her and she takes her life, wondering once more if it was worth it in the end and how things would turn out differently if she hadn't succumbed to the whispering of the dagger.