Schadenfreudler /ˈʃɑː.dɘnˌfrɔ͜ɪd̥.lɘr/

If you don't know how to read IPA, roughly "SHAAH-then-FROYD-ler"

Btw: I just constructed this word based on my native speaker intuition. I doubt that you can find it in a dictionary, because it's not something one would force into a single word. A more natural way to say what you mean would be "Leute, die (hier) (auch) Schadenfreude empfinden", which translates to "people who (also) feel Schadenfreude (here)".