In some situations it is useful to have more than one personality-rich agent interacting with the student at the same time. Doing so allows us vary the approach to motivation in interactions with the student.
For example, the following pairs of agents form a cooperative model that allows us to emphasize different, and sometimes conflicting, pedagogical goals at the same time.
Choleric and Phlegmatic: The former is impatient, demanding attention from e.g., a student Eunice, and a focus on details; the latter is calm, steadying, and supportive.
Competitive and Supportive. One agent competes with, e.g., Eunice, so that she is driven to excel, while another agent acts as a teammate to cheer her on, and share in both her victories and defeats.
Multiple supportive agents. These can act as a chorus of agents that are happy when, e.g., Eunice succeeds and unhappy when she fails. By having such agents engage in dialog among themselves this lends the weight of agreement about the quality of the student's progress, and can help to make clear competing skills (such as performing a task rapidly, but also performing it safely) by personifying them in different (albeit both supportive) agents that care about different things.
Humorous cooperative agents. As above, a dialog among the agents allows more opportunity for humor.
Critical Sad Sack / Champion of the cause. The Sad Sack serves to point out errors the student has made by posing preposterous attacks on the student, while the Champion attacks the Sad Sack (thus allowing the student a feeling of winning, but still not refuting the comments about the student's errors).