ENYALIOS (Enyalius) was a minor god or spirit of war and an attendant of Ares. The name Enyalius, though, was usually just a title of Ares.
ENYA′LIUS (Enualios), the warlike, frequently occurs in the Iliad (never in the Odyssey) either as an epithet of Ares, or as a proper name instead of Ares. (xvii. 211, ii. 651, vii. 166, viii. 264, xiii. 519, xvii. 259, xviii. 309, xx. 69; comp. Pind. Ol. xiii. 102, Nem. ix. 37.) At a later time, however, Enyalius and Ares were distinguished as two different gods of war, and Enyalius was looked upon as a son of Ares and Enyo, or of Cronos and Rhea. (Aristoph. Pax, 457; Dionys. A. R. iii. 48; Eustath. ad Hom. p. 944.) The name is evidently derived from Enyo, though one tradition derived it from a Thracian Enyalius, who received into his house those only who conquered him in single combat, and for the same reason refused to receive Ares, but the latter slew him. (Eustath. ad Hom. p. 673.) The youths of Sparta sacrificed young dogs to Ares under the name of Enyalius (Paus. iii. 14. § 9), and near the temple of Hipposthenes, at Sparta, there stood the ancient fettered statue of Enyalius. (Paus. iii. 15, § 5; comp. Ares.) Dionysus, too, is said to have been surnamed Enyalius. (Macrob. Sat. i. 19.)
Source: Dictionary of Greek and Roman Biography and Mythology.
CLASSICAL LITERATURE QUOTES
Aristophanes, Peace 453 ff (trans. O'Neill) (Greek comedy C5th to 4th B.C.) :
"[The heroes of a Greek comedy try to release Eirene (Peace) from the pit in which the daimon Polemos (War) has trapped her.]
Trygaios (Trygaeus) : As for us, may Fortune favour us! Io! Paean, Io!
Chorus : Don't say Paian (Paean), but simply, Io.
Trygaios : Very well, then! Io! Io! I'll simply say, Io! To Hermes, the Kharites (Charites, Graces), the Horai (Horae, Seasons), Aphrodite, Eros (Love)! But, to Ares (War)?
Chorus : No! No!
Trygaios : Not to Enyalios (Enyalius)?
Chorus : No!
Trygaios : Come, all strain at the ropes to tear off the cover. Pull!"
[N.B. In this passage Ares and Enyalios appear to be two distinct deities.]
- Aristophanes, Peace - Greek Comedy C5th - 4th B.C.
Other references not currently quoted here: Eustathius on Homer 944, Dionysius of Halicarnassus Roman Antiquities 3.48.