Initially Dr. Trefusis might seem totally weird in a crazy-genius kind of way. After all, he's the guy who tries to catch his desk disappearing into the ether by jumping into the room because "He was possessed of a belief that nothing existed, or to be more precise, that only when things were perceived could we be sure that they existed" (1.14.6). While this idea definitely signals a bit of nuttiness is Dr. T, it also works as a bit of a metaphor for slavery—there's nothing natural about it, and it only exists when people are around to, well, make it happen.
Similarly, Dr. T's teaching style is more than a little strange. He likes to tutor Octavian by taking him out on long walks, where he teaches Octavian about things as diverse as the calculation of distance, the science of color, and the philosophy of taxation. As far as this guy's concerned, desks aren't for studying at—they're for testing the existence of being. The more we think about it, the more we wish we had teachers who thought about desks this way.
Call him an odd duck if you want to, but it's clear that Dr. Trefusis is also pretty awesome. This is perhaps clearest when he teaches Octavian all the classic texts about slave rebellion in response to Lord Cheldthorpe's whipping of Octavian and Cassiopeia. It's no surprise, then, that Dr. T's the one who gets Octavian to speak again after that trauma—and to do so with fighting words. Check it out:
He looked down at me; and I began to translate—"In this year, a freeborn slave named Eunus, reputed a magician, rose against his masters…"— while he continued his bellowing over me— "et, manu conservorum comitante, hos contra urbes in Sicilia finites duxit"—until my voice was as loud as his—"…gathering a force of fellow slaves and leading them against cities in the region of Sicily…"—and together, we shouted of servitude, arms, and Rome. (2.2.18)
If you'll excuse us for a moment, we need to grab a tissue. We seem to have something in our eye.
Dr. Trefusis's awesomeness doesn't stop here, though—he's the person who frees Octavian at the end of the book. Not that he's your typical hero with a raging sense of self-righteousness. No, he's more humble than that, and also way funnier. Take his response to Octavian after he drugs Mr. Gitney and Mr. Sharpe:
"It seems," he opined, "a very pleasant day for a walk." (4.12.86)
Ha—this guy is the master of understatements… and slipping his colleagues roofies in order to free Octavian. But he doesn't just buy Octavian a window of time to leave the house with—he goes with him, sticking by his side to continue doing what he can to help Octavian reach true freedom. He might be a little strange, but Dr. Trefusis seems to have a heart of gold.