Delmar is still unaware that after the Titan deity Cronus was defeated, William, in his leisure and seeking amusement, divided Cronus's power into three parts and bestowed it upon Poseidon and his two brothers, thus qualifying them to truly become gods in charge of their respective domains.
This was also because William had watched these three brothers grow up since their childhood and had taught them many things.
Strictly speaking, Poseidon, Zeus, and Hades should all call William 'Master'.
Ah, William always enjoyed seeking fun.
Even the mighty Cronus was considered by William to be too weak, and fighting him was just a way to pass the time, let alone the power of the sea god Poseidon.
Older people often don't like to admit their age, much like William, who always enjoyed playing the role of a younger man.
When he was with Artemis, he even shamelessly called Poseidon 'Master', causing Artemis to burst into giggles.