If I understand well whole video, mask is for all undeads, Fane only designed mask (or concept of mask itself) but is not only one who can wear the mask.
Mask makes you look and sound like other race. If you have lizard face mask you will sound like lizard and others would treat you as they treat other lizards. Same goes for dwarfs and elfes too you only look and sound, but you dont get their skills.

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