Despite his earlier appearances as a stereotypical bully, he has evolved into a good-natured (though extremely boastful) and fiercely protective friend to most of the school's students.

When the Five attempted to do so, they accidentally created a clone formed from portions of his multiversal counterparts who was dubbed Wrongslide.

However, he cares deeply for his friends, recalling the deaths of the depowered students, especially Tag, which usually motivates him to perform feats of incredible strength or bravery.

He also has a strong sensitivity for his teammates, such as when Dust continued to "beat herself up" over the death of Icarus as well as recognizing that he is not supposed to see her without her abaya.

Santo also has a strong sense of honor, telling Anole and Pixie that he would quit the team if they were not included on the roster.