He was a monk of the Kiev Caves, and died in 1188. His uncorrupt relics have wonderworking power. Three fingers of his right hand are to this day raised in prayer, whence it is seen that he died at prayer. This is a commentary on those who do not make the sign of the Cross with three fingers. 
It seems that St Ilya is popularly identified with a legendary Russian bogatyr, or mediæval hero, to whom James Billington refers as ‘perhaps the most popular hero of Christianized epic folklore’, linking him with the Prophet Elijah the Tishbite.  Sir Dimitri Obolensky has published a text with prose translation of one of the byliny (‘oral heroic poems of medieval Russia’ sung in recent centuries ‘by peasant bards’ ) about St Ilya. Here is part of the translation:
It is not a green oak tree bending low to the earth, nor paper leaves fluttering down to the ground—a son is falling down before his father, and begging his blessing: ‘O dear father mine, give me your blessing, that I may go to glorious and royal Kiev town, there to pray to the wonder-workers of Kiev, to do fealty to Prince Vladimir, to serve him in truth and honour, to defend the Christian faith.’
The old peasant Ivan Timofeevich replied: ‘I will give you my blessing that you may perform good deeds, but you have not my blessing for evil ones. When you go on your way, do not harbour evil designs against any Tatar, nor kill any Christian man in the open plain.’
Il´ya of Murom bowed to the ground before his father, mounted his good steed and rode out into the open plain. He strikes the horse on its steep flanks, he strikes through the hide to the black flesh; his fiery steed grows angry, frees itself from the ground, and leaps higher than the standing trees and only a little lower than the passing clouds. At its first leap, it leapt fifteen versts; at its second leap, a well sprung up; by the well he felled a green oak and built a chapel; on the chapel he inscribed his name: ‘A strong and mighty hero rode by here—Il´ya of Murom, son of Ivan.’ The third leap brought him to the neighbourhood of Chernigov town. At the approaches to Chernigov stood a numberless host, at the approaches to Chernigov there stood three [Tatar] princes, each with an army of forty thousand men. The hero’s heart is ardent and impetuous: it flared up hotter than fire, hotter than burning frost.Then Il´ya of Murom spoke these words: ‘I did not want to oppose my father nor indeed to break his commandment.’
He seized his battle saber and began to walk through the host: wherever he wheeled, he hacked out streets, wherever he turned round, [public] squares appeared; he slashed his way through to the three princes. Then Il´ya of Murom spoke these words: ‘O my three princes! Shall I take you prisoners, or shall I cut off your unruly heads? If I take you prisoners I shall have roads for people to ride along and bring me bread. But if I cut off your heads I shall destroy the seed of kings. Go back to your homes and spread the report everywhere that Holy Russia does not stand empty, and that there are strong and mighty heroes in Holy Russia.’
The governor of Chernigov caught sight of him: ‘What a messenger the Lord has sent us! He has liberated our glorious Chernigov town.’ 
There is a brief prose account of some of St Ilya’s more famous adventures here. The comparison of him there to the Arthurian knight, Sir Launcelot, whether or not it is an apt one, reminds me of a wonderful 1940 essay by C.S. Lewis called ‘The Necessity of Chivalry’.  There Lewis, in an attempt ‘to isolate that particular conception of the man comme il faut which was the special contribution of the Middle Ages to our culture’ , cites Malory’s Morte Darthur, Bk. XXI:
‘A, Launcelot!’ he sayd, ‘thou were hede of al Crysten knyghtes! And now I dare say,’ sayd syr Ector, ‘thou sir Launcelot, there thou lyest, that thou were never matched of erthely knyghtes hande. And thou were the curtest knight that ever bare shelde! And . . . thou were the kindest man that ever strake with swerde. And thou were the godelyest persone that ever cam emonge prees of kynghtes, and thou was the meekest man and the jentyllest that ever ete in halle emonge ladyes, and thou were the sternest knyght to thy mortal foo that ever put spere in the reeste.’ 
The important thing about this ideal is, of course, the double demand it makes on human nature. The knight is a man of blood and iron, a man familiar with the sight of smashed faces and the ragged stumps of lopped-off limbs; he is also a demure, almost a maidenlike, guest in hall, a gentle, modest unobtrusive man. He is not a compromise or happy mean between ferocity and meekness; he is fierce to the nth and meek to the nth. 
Of course, Lewis argues that this ideal is as important today as ever:
The medieval ideal brought together two things which have no natural tendency to gravitate towards one another. It brought them together for that very reason. It taught humility and forbearance to the great warrior because everyone knew by experience how much he usually needed the lesson. It demanded valour of the urbane and modest man because everyone knew that he was as likely as not to be a milksop. 
I recommend that all read this essay in full.
 I use the transliteration of the Russian form of this name rather than ‘Elijah’ because it is under the former that St Ilya is most widely known. My standard policy has long been that of thoroughly Anglicising names, but this seems a worthwhile exception.
 St Nicholas (Velimirović), The Prologue from Ochrid, Vol. 4, trans. Mother Maria (Birmingham: Lazarica, 1986), p. 346.
 James H. Billington, The Icon & the Axe: An Interpretive History of Russian Culture (NY: Vintage, 1970), p. 24.
 Sir Dimitri Obolensky, ed., The Heritage of Russian Verse (Bloomington, IN: Indiana U, 1976), p. xi.
 Ibid., pp. 23-5.
 C.S. Lewis, ‘The Necessity of Chivalry’, Present Concerns: Essays by C.S. Lewis, ed. Walter Hooper (San Diego: Harcourt, 1986), pp. 13-6.
 Ibid., p. 13.
 Sir Thomas Malory, Works, 2nd ed., ed. Eugène Vinaver (NY: Oxford U, 1978), p. 725. Lewis quotes only the last lines of this passage, but I thought it worthwhile to give a bit more of Sir Ector's description of the chivalric ideal.
 Lewis, p. 13.
 Ibid., p. 14.