Nightrider is a former Mercenary (now chief) at KMD (Kelidia Military Department). He's serious, stubborn, yet introspective.
His voice is to be slightly gritty and not too deep. There is also a slight bit of tension to his voice, but not to the point he sounds like he's suffocating.

---------- DEMO LINES ----------

(Assertive, serious) "Chief Operator of HOTEL-7 Division 1 at your service."

(Low, serious) "Do not mistake my silence for compliance."
(Low, solemn) "This is for the greater good."

---------- OPTIONAL DEMO LINES ----------

(Low, panicked, serious) "Do not come any closer."
(Low, astonished) "What have you done?"