Sabba – Yes, there is a German ethnic minority in Crimea and they have been there since the end of the XVIIIth/early XIXth century. And no, they were NOT invaders: they were legal settlers.
In fact, there was a time where the Germans were the migrants of Europe and they settled all over Slavic Europe.
Everyone has heard of the Sudetan Germans (aka Bohemian Germans), but there were German ethnic minorities all over central and eastern Europe. For those interested, they may want to look up the Seibenbürgen, the Drang nach Osten or the Ostsiedlung.
These German settlers sometimes ended up taking over what was initially a settlement and ‘germanize’ it to the point where its Slavic roots have been completely erased (for example, Slavic Berlin or all the ‘German’ cities which are located on the eastern side of the river Elbe).
In the cases where they did not manage to take over and change the demographic of the region where they had settled, they have demanded and got a ‘special’ status whereby they had their own schools, their own churches, their own laws (the laws of the land, the local taxes did not apply to them) etc.
In all cases, it is absolutely remarkable that, after so many centuries living among Slavic nations, surrounded by Slavic people, these German ethnic minorities have/had managed to keep their language, their culture, their German identity and… their ‘racial purity’.
Absolutely remarkable.