Oona

Ranger

The evidence suggests Oona is a Ranger. Minrah and Roy call her a Ranger. She dual wields, and she demonstrates tracking ability. Greyview presents as her animal companion, but see below.

Beast Heart Adept

Greyview is a warg (alternate spelling: a worg). A warg is not normally a valid Animal Companion, but Beast Heart Adepts are allowed wargs as a monstrous companion. Oona’s yrthak mount is likewise a valid monstrous companion for Beast Heart Adepts of level 9 or 10. Beast Heart Adepts can have up to three such companions.

A prerequisite of becoming a Beast Heart Adept is spending a week living alone in a dungeon complex. Oona already lives in a dungeon complex; she would only need to find some time alone to qualify.