sajhakohero brother, there is very unclear theory which says that kiratis r distinct race (which is true) n once mighty who ruled from afghanistan to cambodia along the foothills of himalayas. histories of kumaun, gadwal, etc also states that their first ruler of the lands were kiratis. Hazara tribes of afghanistan r also believed to b natives n related to kiratis but there r also another explanation that they were mongolian tribes who were left by genghis khan, thier facial features r of mongol. nagas, lepchas, assamese of india r beleived to b descendent of kriatis too. but in present kiratis denotes only rai, limbu, yakha, sunuwar, tribes of nepal. dhimal, koche, meche hav also made claimed of kirati descendent due to many similarities. in mahabharat, they hav mentioned about kiratis as people who ruled along the foothills of himalayas n precisely mentions the physical and facial features as of mongoloid in nature. it is a strong evidence to somehwat prove that hypothesis of kirats land of influence.

also, there r many interesting stories about origin of deusi in kirati folklore, even though now it is known as one of the events in hindu festival tihar but the funny part is why dont the hindus in india or other regions do deusi n also bhai tika but remains as one of the unique celebration in nepal. also the tradition of eating taro ot tarul in maghe sakranti goes back to kirat period as a gesture n respect of how our ancestors survived before they knew the skills of harvesting. they r mentioned in kirati folklore. many scholar beleives it is possible that they hav been hinduinised to current form being the dominant and conventional religion but has brought uniqueness as nepalese festivals since many such celebrations r found to b none in hindus of other regions.  if u r interested i can post sum of them right here.