Nightwolf is the main character from the games in the Nightwolf series. He is a black wolf and is one of the bearers of the Crimson Gem. In terms of the Crimson Gem, he is the successor to both Crimson and AntiWolf. Nightwolf is distrusting of people he does not know.
Nightwolf died between the Nightwolf Octilogy and the Crimson Trilogy. Despite this, he appears as a half-spirit in Nightwolf: All Wrapped Up