Yu-Gi-Oh! Zexal - S1E19

Events of Happiness

Yuma misplaces the the Emperor's Key that was an important momento from his parents. He and Astral look high and low for it, but they just can't seem to find it. While they look, Astral is curious as to how the Emperor's Key is related to Yuma's father. Yuma starts talking about various memories from his childhood that he remembers about his dad. Yuma's Never-Give-Up Spirit "Kattobingu" was born from a promise he made with his father.