|"You are, of course, welcome to speak with Rowanstar. Will he know what this is about?"|
|— Nightmask talking with Lionstar and Greeneyes in Code of the Clans, page 104|
Nightmask is a tom.
In Code of the Clans, he is an ancient SkyClan deputy serving under the leadership of Rowanstar. When Lionstar, the leader of ThunderClan, and Greeneyes, the deputy, come to speak with Rowanstar, the SkyClan leader, they accuse him that his warriors are spying. Nightmask meets them in the middle of the camp and greets them and nods respectfully. He says that they are welcome to speak with Rowanstar, then asks if Rowanstar is expecting this. Greeneyes then hisses that it was about SkyClan's warriors spying on them.
- Code of the Clans (First appearance)