Considering the serious storyline of the DBZ, he serves as the
comic relief.
When Cell called for the best warriors in the world to challenge him in the Cell
Game, Mr. Satan, the world boxing champion answered the challenge and declared
himself the savior of the world.
He regarded the powers of Cell and the Dragon Ball Warriors as mere
"illusions." Even when the whole world shook in the epic battle
between Son Gohan and Cell, he stood firm to his view. However, even though he
did not outwardly admit what he saw was very real, his cowardly excuses to avoid
battle and taking the credit for defeating Cell readily demonstrated otherwise.
Mr. Satan fooled the whole world of his powers and continued to do so when he
paid off #18 for his title in the Budokai after Cell was defeated.
The most interesting portion of his presence in DBZ was his friendship with
Majin Buu. Like no one else, he brought out the "good" in Buu and even
convinced Buu not to kill anymore.
Despite of his lies, Mr. Satan did contribute to his share to saving the earth.
In the Cell Game, it was him who brought what was left of #16 to Son Gohan, who
ultimately drove Gohan's spirit to transform into Super Gohan.
He also contributed to the defeat of Majin Buu by convincing everyone to
contribute their share of energy to Son Goku's Kenki Dama which ultimately
destroyed Buu.