Petarus and Vanja
They are a somewhat unusual couple - Petarus is an ex-Blackguard who decided to rescue Vanja, an exile soon to become a subject of Piety's experiments, and abandoned The Ebony Legion. They escaped to Highgate, and are inseparable ever since.
Petarus and Vanja been accepted into Highgate by Oyun as the first foreigners in two centuries - much to Kira's disgust. They are clearly very grateful for her aid, and besides Kira, they seem to be generally liked throughout Highgate, sharing knowledge and stories of the outside world with the long-isolated Maraketh people.
As Tasuni puts it, Petarus and Vanja seem to be "two mouths speaking from one mind" - they seem literally inseparable, even as far as completing each other's sentences while speaking. There is notable contrast in their character, and the mild-mannered Petarus sometimes appears a little overwhelmed by Vanja's energetic, strong-willed nature. But despite their near-constant bickering, they obviously care deeply for each other, and contrary to their sometimes slightly childish behaviour, they both appear to be quite intelligent and offer plenty of interesting information and insight.