Nircurus Felkus was a Great Knight captain noted for his cunning and calculating personality, earning the nickname "Fox" purely because of this. He rose to prominence during the Lostathon Campaign, in which Nircurus took charge after his commander was killed and successfully destroyed an enemy detachment with complex heavy cavalry tactics. Although Nircurus relied on his partially psychopathic nature to allow him to command properly, he still cared for his troops, understanding that their morale was vital for success, and disliked participating in torture, only using it when necessary. He was later part of the Eclipse Expedition and constantly jostled with Tangeldis, disliking her authoritarian nature. He was already friends with many of the Great Knights on the expedition, especially Parean, Vince and Samson - with similar tactical thinking as Parean and Samson, the three got on extremely well, often discussing strategy in their free time. He eventually defected to Chaos with most of the Great Knights, dissatisfied with their leadership, and ended up defeating Vince in several battles towards the end of the latter's rebellion.
- Nircurus' name is based off the Sindarin word for "man of craft" or "cunning", referring to the wizard Saruman, whose Sindarin name was "Curunir"
- Nircurus himself is based of a few successful generals in history, particularly Erwin Rommel, even using a quote by him, but personality-wise is also much more different, being less abrasive, and significantly more tolerant and controlled