There is Guts, the protagonist from the manga and anime Berserk. Guts. Götz. It’s right there, right?
The manga debuted in 1989, and although Guts fights with a sword, he boasts a prosthetic arm (like Götz!) that also features a built-in cannon (like Sieger!), which he uses in fights. Just based on the similarity of their names alone, you might assume that Guts has to have been inspired by Götz, but apparently that is not the case: In this interview, Berserk creator Kentaro Miura says it’s all a coincidence.
“I’ve heard about this knight who helped a peasant revolution in Germany, and the knight’s name was [Götz], and he had an iron artificial arm. When I found out about it, I thought it was a strange coincidence. I don’t know if he shot arrows from it. It was especially uncanny because I had already started Berserk. I wasn’t really thinking of anybody at the time I created Guts.”
You can decide for yourself if you think he was being truthful in saying that, but it’s worth considering that in the very next breath, he owned up to Guts’ physical appearance being inspired by Rutger Hauer’s character in the 1985 movie Flesh and Blood. He’s clearly willing to credit his inspirations.
Let’s say Miura was being truthful. If we’re going to believe that it’s a coincidence that he created his iron-handed hero completely independently from this similar one from history, should we imagine that the idea for Samurai Shodown’s iron-handed German dude could have arisen separately as well? I suppose that’s possible, but I think it’s more likely that the team that made Samurai Shodown II would have been familiar with Berserk, maybe even liked it to the point that they wanted to shoehorn Guts into the game. If they did this, they’d probably do it under the guise of a real-life figure from history, in the same way that they used Charlotte Corday to sneak in Oscar from Rose of Versailles in the first game.
The connection is all about the little touches. Guts got his name because it “sounded somehow like a German name,” per this 1996 interview with Miura, but he’s not German because Berserk takes place in a fictional world. Sieger is Prussian, and while Prussia is not “old Germany,” strictly speaking, I do feel like that’s how SNK is using it in Samurai Shodown II — like it’s the Teutonic stand-in for Edo era Japan. Neinhalt Seiger’s name, for what it’s worth, translates from German as “no-stop winner,” which makes for bad English and I think bad German too, but it outdoes Guts for indeed sounding very “like a German name,” at least if you don’t speak German.