The Swan Knight
In this account the swan knight’s name was Loherangrîn, and he was the son of Parzival (Perceval), the Grail hero, and heir to Parzival’s title; he arrived in a swan-drawn boat from the castle of the Grail to aid Elsa of Brabant, married her, and in the end returned to the Grail castle.
https://www.britannica.com/topic/Lohengrin-German-legendary-figure
White Swan is Purity and Grace
Black Swan is sign of the Occult
https://worldbirds.com/swan-symbolism/