Aruku is a knight serving the Lingle Kingdom. He is a young man of notable talent, possessing both exceptional swordsmanship and proficiency in magic. His abilities are considerable enough that he would qualify for a position among the kingdom's royal guards. However, despite his high level of competence, Aruku chooses to serve in the more modest role of a castle gate guard.

In terms of personality, Aruku is portrayed as an honest and dedicated soldier whose primary focus is the protection of the castle. He appears to possess a degree of humility or self-awareness, as he reportedly claims to be clumsy, which is part of his reasoning for not pursuing a more prestigious post within the royal guard. His decision to work as a gatekeeper rather than seeking glory suggests a down-to-earth character who is content with his duties.

Regarding his combat abilities, Aruku stands out for his unique fighting style. He can integrate fire magic directly with his sword techniques, creating a combined attack that is highly powerful. This skill makes him a formidable fighter among the knights of the kingdom.

His role in the story is that of a supporting character. As a knight of the Lingle Kingdom, he is among the soldiers who protect the realm and its people. His position as a gate guard means he is often one of the first points of contact for those entering or leaving the castle. Specific details about his key relationships with other characters are not provided in the available information, beyond his general association with the kingdom's military forces. Similarly, there is no documented information about any significant character development or personal motivations beyond his dedication to his duty as a soldier.