serepim
שרפימ
'serepim' is the plural personification of serep (“roast”) so it appears to mean “Roasting People”, possibly a specialized BBQ chef or “grillmaster”.
This word has traditionally been mistranslated as some kind of mystical and ethereal being, a type of “angel”, and typically pronounced as Sareph. There is no indication within the text that the serepim are non-corporeal or possess superhuman power.
Indeed, the word occurs only 3 times and the references do not give detailed description other than to indicate that they have hands and are seen moving coals around in a fire.
Numbers 21:6 speaks of the grill masters in association with copper craftsmen and the imposition of a tax by Ihoh
In Isaiah 6:6 the grill masters are described working the burning coals with tongs.
Isaiah 6:2 is somewhat more cryptic, requiring further analysis.