Personality:
-bit passive aggressive
-is often patient, although that can   change depending on the people he is around
-mischievous
-likes to confuse people
-likely to hold a grudge (KITT and Michael for example
-sees himself as superior to KITT
-can be quite nice to be around once you have his trust

Backstory:
After he got destroyed, he did not even care anymore about his original programming. His only goal is/was to destroy KITT and kill Michael. When Chlara found him, that hadn't changed a bit. However, it seems that he is still confused about Chlara being so fond and protective of him, since she knows about his past. Nonetheless does she seem to fully trust him. We'll see how that plays out...