Jova Tarkin is a human of the Tarkin family of Eriadu and the paternal grand-uncle of Wilhuff Tarkin, introduced in James Luceno's Tarkin (Del Rey, 2014). He completed the family's traditional initiation in the Carrion Plateau and then did something no Tarkin had done before: he stayed, built a cabin, and made the wilderness his permanent home.
That made him the lineage's instructor. He personally took both Wilhuff's father and Wilhuff himself through their coming-of-age ordeals in the plateau — the survival apprenticeship that Luceno's novel treats as the origin of the Grand Moff's entire doctrine. Everything Tarkin later says about fear and control he learned from an old man in the bush who was teaching him how not to be eaten.
Catalogue entry. This figure has a verified record here rather than a full write-up — the encyclopedia labels its own depth instead of padding it.