Daniel Callahan’s voice should be relaxed and slightly raspy, with a tone that combines weariness with wit. He carries a casual air, almost irreverent, but is sharp and clever, so the delivery should be laid-back but with an undertone of intelligence. References like the sarcastic charm of Tony Stark (Robert Downey Jr.) can capture the balance between humor and cleverness. Articulation is clear, but the pacing reflects his more laid-back, detached attitude.