"Caroleans (Swedish: karoliner), from Carolus, the Latin form of the name Charles, is a term used to describe soldiers of the Swedish army during the reigns of Kings Charles XI and Charles XII of Sweden, and specifically from 1680, when Charles XI instituted an absolute monarchy."

That is what Wikipedia says in answer to your question.

We do our own research and never use that terminology to describe King Charles I and King Charles II, both of whom were individually the King of England and the King of Scotland, but never the King both of England and Scotland as one united kingdom.