A knight? Not a masseur? Meh... 8)
Not sure what you mean by an "active" knight - if you mean currently sworn to a lord, the Social Status virtue doesn't really address that, but there would still be some relationship there, some higher lord to whom he's sworn, who made him a knight, or whatever. Perhaps the relationship is dormant, but it's there at some level.
In some cultures (and certainly in the genre in general), there are also Knights Errant, who wander about "doing good work". Their lord or duties have given them leave to do this, so... great!
A "warrior" is merely someone who is in the combat business - could be a noble, could be a scummy peasant. A Knight has social privileges and rank above the common man, and the two are as different as someone who has studied politics and a Kennedy (if you'll excuse the analogy.) Beyond that, how you depict the knight is up to you, and your Troupe.
(Edit: But if it were me, I'd suggest something like:
Puissant Alertness (another result of the blinding - crucial for those "other senses")
possibly Privileged Upbringing
possibly Strong Willed (to not give up after blinding)
possibly Temporal Influence (depending who his family is, etc)
possibly "Famous", to help counter the blindness
(Things like "Tough" could work too, but he may be "out of shape" since the blinding, etc.)
Some Personality Flaw as result of Blinding - Driven, Wrathful, Fear, OverSensitive, Pious, Vow, etc
possibly Disfigured, depending on how blinding was done
possibly Mentor, someone who can guide him on his new dark path
Careful about the Story flaws, this character could easily fit too many.