It was Astrid who managed to sneak into the cities of Zephyria, she disguise herself as one of the Asgardian soldiers whose job was to send food and weapons supplies to the soldiers in the city.
From the information Astrid got from her reconnaissance, Tristan immediately made a siege plan to liberate the cities from his enemy's control, which he planned to be carried out within a maximum period of three days.
In order to save time, he divided his team into two groups, one was besieging the city of Zephyria, while the other was besieging the city of Nexusia. But of course, they would carry out a similar operation, where one team would wreak havoc to distract enemy forces while the other team would go and free the hostages.
After deep contemplation, the Blood Warrior Tribe led by several elves would be the one to wreak havoc and distract the guards at the main gate.