Namtose is a "protector" in the Karma Kagyu scheme of things....he's also known as one of the 4 directional gaurdians. He's also associated with "wealth."
Namtösa is the Tibetan name of Vaishravana who is ,as has been said before, the guardian of the northern direction associated with wealth. He is also one of the Karma Kagyu protectors of the Khor Nga.
Oops, didn't read the original comment, only the question about what "Khor Nga" meant. You're correct, of course, about the "Mandala Of Dorje Bernagchen" and the five "retinue."