"niemal" doesn't exist; "niemals" is stronger than "nie". (edit: cross-posted...)

Often, both sound equally natural: "Ich würde nie(mals) einen Menschen schlagen" ("I would never hit a person") - but if you don't need the added emphasis, you'd stick with "nie": "How often do you go to the cinema?" "Ich gehe nie ins Kino." ("I never go to the cinema")

With imperatives, "niemals" seems a bit more common, anyway if it's supposed to be urgent: "Drücken Sie niemals diesen Knopf!" ("Never press this button!")

I'd say "nie" and "niemals" are synonyms. "niemal" doesn't exist.

Hello x_Ice_Elf! Here is an excerpt from a comment on one of my posts concerning "Nimmer", "Niemals" and "Nie".

It's from Mia797420

nimmer - old fashioned niemals/nie - synonymous / nie seems to be more common

Und sie ward nimmer mehr gesehen.

Ich fahre nie in den Urlaub.

Das würde ich nie machen. Ich habe ihn noch nie gesehen.

Niemals würde ich das machen.

Sag niemals nie.