Newar is not a cast, it is a culture. That is why we have several casts inside newars, like bharman in newar (eg. shakya etc.. and lower caste like japu and maharjan...) The origin of newars can be associated with south indians. for eg. in every religious occasion newar needs Supari(beetle nut) same as in south india. there is now way you can get supari in kathmandu. there are other numerous example as well, but i can't think of those now, i need to get out and showel this nor-easter... and there is nothing wrong about knowing your roots...