There are three accents in Greek. No Greek accent can stand farther back than the antepenult.
1. Acute (/): over short or long vowels and diphthongs. It may stand on ultima, penult, or antepenult: καλός, δαίμων, ἄνθρωπος.
2. Circumflex (=): over vowels long by nature and diphthongs. It may stand on ultima or penult: γῆ, θεοῦ, δῶρον, τοῦτο.
3. Grave (\): over short or long vowels and diphthongs. It stands on the ultima only: τὸν ἄνδρα, τὴν τύχην, οἱ θεοὶ τῆς Ελλάδος.
Herbert Weir Smyth [n.d.], A Greek Grammar for Colleges; Machine readable text [info] [word count] [Smyth].