The Khambu Rai script is used for writing Bantawa, a Tibeto-Burman language spoken by members of the Rai ethnic group in the Eastern hills of Nepal. Bantawa is generally written in the Devanagari script, and literacy in this writing system is over 50%. Bantawa can also be written in the Khambu Rai script, which was designed for this purpose in the 1980s by Kripasalyan Rai. Khambu Rai is an abugida; every consonant contains an inherent vowel, which can be modified by the use of vowel diacritics. Multiple consonant sounds occuring together in a cluster, with no intervening vowel, may be written with special ligatures. It is unknown to what extent the Khambu Rai script is used.
This script is not currently recognized by the ISO 15924 standard, but is included in ScriptSource for research purposes. If you have any information on this script, please add the information to this site. Your contributions can be a great help in refining and expanding the ISO 15924 standard. The Script Encoding Initiative is working to support the inclusion of this script in the standard, and contributions here will support their efforts.