1. According to Hesychius and the Etymologicum M., a surname of Zeus, describing him as the avenger of evil deeds. But the name is also used, especially by the tragic writers, to designate any deity or demon who avenges wrongs committed by men. (Paus. viii. 24. § 4; Plut. De Def Orac. 13, &c.; Aeschyl. Agam. 1479, 1508, Pers. 343; Soph. Track. 1092; Eurip. Phoen. 1550, &c.)
2. A son of Neleus and Chloris. When Heracles took Pylos, Alastor and his brothers, except Nestor, were slain by him. (Apollod. i. 9. § 9; Schol. ad Apollon. Rhod. i. 156.) According to Parthenius (c. 13) he was to be married to Harpalyce, who, however, was taken from him by her father Clymenus.
3. A Lycian, who was a companion of Sarpedon, and slain by Odysseus. (Hom. Il. v. 677 ; Ov. Met. xiii. 257.)
4. Another Alastor is mentioned in Hom. Il. viii. 333, xiii. 422. [See TROS, No. 2.]