So, is it you who keeping up with the 'Black Clover' universe? Excellent! As for your question, Yami and Charlotte, or shall we call them Chi-Mi-rato-Lianott?The history of their relationship is a charmingly slow burn, Almost invisible but still present throughout the series, Charlotte has always been consistently affectionate towards Yami despite her tsundere nature.
However, since the kind of shōnen series they both inhabit seldom makes any effort to develop romantic relationships (although exceptions like Naruto and Bleach abound), they have yet to officially come together. Canonically, they are not lovers. But they still share lots of very sweet moments that definitely indicate love on both sides.