Island of Blood

The Island of Blood has been such an outpost for all these millennia, dating back to the time of the first invasion of Chaos. The island is shrouded in mist, surrounded by treacherous rocks and reefs, and is protected by magical wards. Only the High Elves know of the secret sea-route that needs to be followed in order to reach the island in safety.

A small garrison protects the outpost, recruited from the legendary Swordmasters of Hoeth and watch over by an Archmage from the White Tower of Saphery. Horribly outnumbered by the invading Skaven horde, the High Elves have been forced to send a mystical call for help. This desperate plea has been answered by Prince Altharan Stormrider, who has rushed to the island to aid the beleaguered defenders.

Source
pg. 8
 * Island of Blood (supplement)