AlastoryoudaoicibaDictYouDict[Alastor 词源字典]
in Greek tradition, son of Neleus, brother of Nestor, slain by Herakles. The name is perhaps literally "not to forget," from privative prefix a- "not" + root of lathein "to forget" (see Lethe), hence its use figuratively in sense of "an avenging spirit." Or else it might be connected with alaomai "to wander, roam," figuratively "to be distraught."[Alastor etymology, Alastor origin, 英语词源]