Yup, they are truly scary. In addition to there being six, they are directly under the eye, very long and about as mobile as a vipers but also can swing slightly outwards.
:What are the other ones with more than two?Is this trait common in rear fanged snakes?
With most of the 'rearfangs' (and I use this term very loosely) the teeth are in enlarged groups. Not many have true 'fangs' per se. However, this doesn't mean too much. Some of the ones I'm working with have all the teeth slightly enlarged and very very sharp. So, the difference between 'no fangs' and 'rear fangs' is very artificial.