It's St. Maurice, also the namesake of the town's church. So how did St. Maurice end up being depicted as a black African and why was he so popular in Germany? Well there are a couple of older answers that tackle this question:

If there was an African population (Ethiopians) in Rome, albeit a smaller population, what happened to them in Europe throughout the medieval age? And what happened to Europeans’ collective perception of Africans by u/sunagainstgold

Did non-white nobility/knights exist in medieval europe? by u/SpartiateDienekes