What do the yellow damage numbers mean?

I've been playing for a few months now and I am still unsure on what the yellow damage numbers with the small sword icon mean. I usually see them when my Nautika casts her attack incantations or when Semmelweis does that follow up attack when she has her array up.

I tried looking it up but I couldn't find anything about it (or maybe I just wasn't looking hard enough). I wonder if I missed the explanation for this when I started playing (I wasn't quite paying attention on the tutorials since I was too overwhelmed by new terms and all).