Voltage, Current, Angular Velocity, and the effect they have on Torque
Torque is directly proportional to current. One of the motor specifications is the torque constant, Kt.

Torque = Kt * current

The voltage and angular velocity play only an indirect role. The voltage is what creates the current, and the angular velocity creates the BEMF that reduces the available voltage (thereby reducing the current, which then reduces the torque).

As a demonstration, take a motor, push a voltage through it with no load, and it will accelerate to a speed where the back-EMF balances the input voltage. You have little torque, and also not a lot of current. Now try to slow the motor down. As you do, the back-EMF drops, allowing more voltage to drive the motor, increasing the current and the torque. The motor is fighting you to keep spinning, and that requires more current.

If you use a current-mode amplifier to drive the motor, you can directly control torque, without regard for the voltage.

This is true for all motors: brushed, brushless, induction, permanent magnet, or stepper.