Fun fact: Allan was supposed to be just a throwaway character, but he sort of took on his own life and became something truly lovable.
Minor characters are fun for me because they have lives outside the hero. It's really helpful for each character to have a somewhat rich backstory, even if it's just a few sentences about what they want in life and what drives them- that way, they inadvertently affect the hero in some way and make the story more interesting.
While Allan is loyal to the Emerald Dragon, at the end of the day, his loyalty stems from his belief that she keeps his home, wife, and daughter safe from those who would harm them.