If the Beckoned ordered Secandra to spare the Jottun, the book reads as follows:
Our hero/ine soon learned of the Kollossae plight. In order to meet the Primos, s/he would have to repel the Jottun horde that endangered the people of Idylla. Much to the surprise of Secandra, our hero/ine was able to kill the Jottun Warlord, effectively ending the Jottun threat. In yet another act of generosity, s/he convinced Secandra to let the remaining Jottun live, which unbeknownst to her/him then, would one day prove a boon.
Why did s/he want to spare the Jottun? It may have been mercy, or pity. I will not pretend to know the motivations of my one-time companion. From the moment I met her/him I knew there was something different about her/his character, but don't trust me to name it. I am a man of action, not of words, and describing the thoughts of the Beckoned is beyond my ability.
Regardless of why, the Jottun knew they were spared, and recognized the Beckoned as their savior. Without the ruthless Kahrunk leading them, they began a new way of life, less intent on destroying the Kollossae, albeit still savage.
If the Beckoned ordered Secandra to exterminate the Jottun, the book reads as follows:
Our hero soon learned of the Kollossae plight. In order to meet the Primos, s/he would have to repel the Jottun horde that endangered the people of Idylla. Much to the surprise of Secandra, our hero/ine was able to kill the Jottun Warlord, which left the Jottun horde disorganized and vulnerable. Secandra's forces finished the conflict by killing most of the remaining Jottun. The ogres stood little chance against the organized might of the Kollossae. Although our hero/ine did not witness the destruction of the Jottun people, it was so thorough that there were very few left in the Teeth outside their crude tower.
I was told that our hero/ine encouraged this slaughter. Why? Your guess is as good as mine. True, s/he was my companion, if at least for a short while, however I make no pretenses of knowing her/his thoughts. Perhaps it was to gain the trust of her/his new allies. It may just be her/his way to leave a legacy of bloodshed in her/his wake.
For whatever reason, the Beckoned promoted the massacre, and the Jottun were effectively gone from the Teeth of Naros.