The Citadel is an archive of information for George R.R. Martin's A Song of Ice and Fire.
New to the series? Read our spoiler-free review of A Game of Thrones.
The overly-coincidental arrival of his brother Euron Crow’s Eye (III: 524) suggests that there is more than meets the eye to Balon’s death. The Ghost of High Heart revealed this prophetic vision which seems to have some bearing: “I dreamt of a man without a face, waiting on a bridge that swayed and swung. On his shoulder perched a drowned crow with seaweed hanging from his wings.” (III: 249) The common interpretation of this is that the "man without a face" is a Faceless Man and that the drowned crow represents Euron as his hirer. Euron is known for having travelled widely, from the Summer Isles to the Free Cities and beyond to Asshai, and would certainly have had the opportunity and funds (thanks to his reaving and pirating) to hire a Faceless Man.
The Westeros network consists of several different sites, including a forum and a wiki, for all your A Song of Ice and Fire needs.