Jet of red sparks
Vermillious is a charm that precipitates vermilion sparks from the wand tip; these sparks emit a reddish smoke from them as well. They can be directed towards another to do damage, for example, in duelling, or against plague rats. It is the lesser variant of Vermillious Duo and Vermillious Tria.
From the English word vermilion, which is a shade of brilliant red.