Relative Clauses of Cause take the indicative (negative οὐ). ὅς is more common than ὅστις.
θαυμαστὸν ποιεῖς, δς ( = ὅτι σὺ)
ἡμῖν . . . οὐδὲν δίδως
a deed most unhallowed, cheered me with words, etc.
a. γε is often added to ὅς or ὅστις.
b. μή is used when there is also an idea of characteristic (
Herbert Weir Smyth [n.d.], A Greek Grammar for Colleges; Machine readable text [info] [word count] [Smyth].