Looks like good one TR period made I have just did some online search and found that jeweler mark belongs to Karl Martin from the House of German art Here is another brooch by the same jeweler with the same maker mark
Here you go Ado. Same mark, same maker. Different engravings on the dragon heads, so it is a bit different than yours. Very large and impressive brooches! Maybe someone can find more of these by this maker - hopefully.
just in time for Christmas: a brooch with provenance as written on the original jeweler box, a gift from a ss officer in Norge to a party-member's wife