The dark Fates, gnashing their white teeth, terrible-faced, grim, bloodred, dreadful … all eager to drink black blood

From Hesiod’s Aspis / The Shield of Herakles (249-270). Terrifying – and seems a rare glimpse in early Greek poetry of what might be folk beliefs/conceptions not polished into presentability.

…. the dark Fates, gnashing their white teeth, terrible-faced, grim, bloodred, dreadful, were engaged in conflict around those who were falling. They were all eager to drink black blood. Whomever they caught first, lying there or falling freshly wounded, she clenched around him her great claws, and his soul went down to Hades to chilling Tartarus. When they had satisfied their spirits with human blood, they would hurl him backward, and going forward they would rush once again into the battle din and melee. Clotho and Lachesis stood over them; Atropos, somewhat smaller, was there, not an especially big goddess, but nonetheless she was superior to these others and the oldest one. All of them were waging bitter battle around one man; they glared terribly with their eyes at one another in their fury, and upon it they were equal to one another in their claws and fierce hands. Beside them stood Death-Mist, gloomy and dread, pallid, parched, cowering in hunger, thick-kneed; long claws were under her hands. From her nostrils flowed mucus, from her cheeks blood was dripping down onto the ground. She stood there, grinning dreadfully, and much dust, wet with tears, lay upon her shoulders.

Κῆρες κυάνεαι, λευκοὺς ἀραβεῦσαι ὀδόντας,
δεινωποὶ βλοσυροί τε δαφοινοί τ᾽ ἄπλητοί τε
δῆριν ἔχον περὶ πιπτόντων· πᾶσαι δ᾽ ἄρ᾽ ἵεντο
αἷμα μέλαν πιέειν· ὃν δὲ πρῶτον μεμάποιεν
κείμενον ἢ πίπτοντα νεούτατον, ἀμφὶ μὲν αὐτῷ
βάλλ’ ὄνυχας μεγάλους, ψυχὴ δ’ ᾌδόσδε κατῇεν
Τάρταρον ἐς κρυόενθ᾽· αἳ δὲ φρένας εὖτ᾽ ἀρέσαντο
αἵματος ἀνδρομέου, τὸν μὲν ῥίπτασκον ὀπίσσω,
ἂψ δ᾽ ὅμαδον καὶ μῶλον ἐθύνεον αὖτις ἰοῦσαι.
Κλωθὼ καὶ Λάχεσίς σφιν ἐφέστασαν· ἣ μὲν ὑφήσσων
Ἄτροπος οὔ τι πέλεν μεγάλη θεός, ἀλλ᾽ ἄρα ἥ γε
τῶν γε μὲν ἀλλάων προφερής τ᾽ ἦν πρεσβυτάτη τε.
πᾶσαι δ᾽ ἀμφ᾽ ἑνὶ φωτὶ μάχην δριμεῖαν ἔθεντο·
δεινὰ δ᾽ ἐς ἀλλήλας δράκον ὄμμασι θυμήνασαι,
ἐν δ᾽ ὄνυχας χεῖράς τε θρασείας ἰσώσαντο.
πὰρ δ᾽ Ἀχλὺς εἱστήκει ἐπισμυγερή τε καὶ αἰνή,
χλωρὴ ἀυσταλέη λιμῷ καταπεπτηυῖα,
γουνοπαχής, μακροὶ δ᾽ ὄνυχες χείρεσσιν ὑπῆσαν·
τῆς ἐκ μὲν ῥινῶν μύξαι ῥέον, ἐκ δὲ παρειῶν
αἷμ᾽ ἀπελείβετ᾽ ἔραζ᾽· ἣ δ᾽ ἄπλητον σεσαρυῖα
εἱστήκει, πολλὴ δὲ κόνις κατενήνοθεν ὤμους,
δάκρυσι μυδαλέη.