The Obsidian Trilogy is a three-novel fantasy series, chronicling the journey of Kellen Tavadon in relation to the third war between the Light and the Endarkened, co-written by Mercedes Lackey and James Mallory. The series began with The Outstretched Shadow, released in 2002, continued in 2004 with To Light a Candle and reached its conclusion in 2006 with When Darkness Falls.