The story
Transliteration of Old Church Slavonic Иаоиль (Iaoilĭ), from reconstructed Greek Ιαοὴλ (Iaoḕl), from reconstructed Hebrew יהואל or יואל; thought to be a compound of the Tetragrammaton, יהוה (Yahweh or Yahoh), and אֵל (ʾēl), both used as names of God and the latter a common ending of personal names.
Etymology from Wiktionary, CC BY-SA 4.0.