Cohmac Vitus is a human Jedi Master, a scholar and mystic created by Claudia Gray for Into the Dark (2021). He was mentioned first in Light of the Jedi as a Knight; Gray's novel, where he actually appears, makes him a Master.
The Eiram–E’ronoh crisis
As a Padawan, Vitus was caught up in a war between the neighbouring worlds Eiram and E'ronoh, and lost his own master to it. Twenty-five years later he is still carrying it, and the High Republic's institutional confidence — the Order at what it believes is its height — reads to him as an unwillingness to examine what it costs its own people.
Drifting
Across Into the Dark, Out of the Shadows and Midnight Horizon he moves steadily away from orthodoxy, in the company of his Padawan Reath Silas and his crèche-mate Orla Jareni, who has already left the Council's authority to become a Wayseeker. He is not a fall-to-the-dark-side story. He is a resignation story, which the franchise attempts far less often.
Why he matters
Because the Phase I novels are largely about an Order that is admired, well funded and entirely sure of itself, and Vitus is the internal dissent. Without him the era would have no one asking the obvious question from inside.