A Seer of Rage knows/understands Rage or knows/understands through Rage (generally in a conceptual way) for the benefit of others.

A Thief of Mind steals Mind or steals through Mind for their own benefit.

     This is quite the interesting pairing! I see a Thief of Mind “stealing” the personalities, traits, and attitudes from media (such as a common trope, being part of a fandom, or a social media trend, perhaps?) and other people, likely stealing new things so often it’s close to normal for them. 

     The Seer of Rage, who hates lies and the stability false ideas can impart, would certainly have things to say about the Thief of Mind. I see the Seer of Rage as being obsessed with tearing down the stolen identities and personalities of the Thief of Mind, or maybe they just immediately see through their stolen identities and quirks, knowing that all of the different personality quirks stolen are just empty and vapid crap. 

     A relationship between these two could go very different ways. In a flushed context, the Seer of Rage would understand the empty, fluid nature of the Thief of Mind, allowing them to get to actually know the “true” Thief of Mind. The Rage-bound are original and fearless at their best, so I could see the Seer of Rage causing the Thief of Mind to understand how to be original and fearless themselves; they could teach and guide them (moirallegiance?), or the Thief of Mind might passively understand how to be original just by observing and being around the Seer of Rage, ironically stealing from their identity...but in a more constructive way.

     Going the complete opposite direction, towards kismesissitude or just a plain disliking, the Seer of Rage would be obsessed with tearing down the stolen identities and quirks of the Thief of Mind, because they just don’t like them? Or maybe they want to “expose” them? The Seer of Rage’s uncanny ability to see through the Thief of Mind’s fluid and unoriginal personality would definitely make the Thief of Mind uncomfortable. I’d find it likely that the Thief of Mind (particularly a Dersite) would put great care and thought into their front of an identity, making it that much more painful when the Seer of Rage tears down the front, revealing the Thief of Mind’s compensation for their inherent lack of rational thinking and outward identity.