Pharaoh was Lyman Banner's cat. Whilst Banner was alive, he had a relationship with Pharaoh. He was rarely seen without him, even at official school meetings.
Vellian Crowler had a great dislike and fear of Pharaoh, often claiming that the cat had rabies or other diseases.
After Banner's spirit was freed, it began to live inside Pharaoh. Banner's spirit emerges to support Jaden several times throughout the series, but each time Pharaoh eventually swallows his soul again.
In the last episode Pharaoh is the one who gives Jaden Yuki the note that was given to him from his friends before going out to his adventure.
Currently, Pharaoh, along with Lyman Banner's spirit, is travelling with Jaden.
In Yu-Gi-Oh! 3D Bonds Beyond Time, Pharaoh and Banner's spirit accompany Jaden during his search for Paradox. He is transported to the past and watches the Duel. Later he returns to his own time with Jaden.