Slade's parents never died therefore, Slade never had the chance to meet the Sevilles....until now.
Alvin and his brothers Simon and Theodore got kicked out of they're old school and are now being transferred to a new school. This particular school holds a lot of talking chipmunks. The only humans were the staff. This makes it easier for the brothers to fit in.
Slade, who supposedly runs a small gang in the school, has made a job for himself and his crew. They would keep everyone in the school in check. If anyone stepped to them, it usually would end with a beating. Slade notices Alvin almost immediately after he steps foot on campus. Slade soon became Alvin's bully. Slade would tease and shove Alvin around but if Slade sees someone else do this to Alvin, Slade is quick to defend him. Is this just because Slade hates seconds or does Slade have feelings for Alvin and just doesn't know how to show it properly.