Hey, Pelliot, the Ruby Holy Knight fighting Pellegarde this episode was actually a character in the original Seven Deadly Sins. So, he is a nostalgic character for people who have seen the prequel. Especially manga readers, because his story was kind of different and gave us a better emotional connection. In the prequel he was just a small kid who wanted to be like Meliodas. To see him get this far is really cool for manga readers like me. He's strong now, and has a cool magic power, too.
0:50 Her name changes depending on the language: in English it is Guinevere, in Spanish it is called Ginebra, it is much easier to say her name like that.
Also, in the timestamp 2:28, Gawain actually appears in the background, just walking past, as the other knight was wearing her armor. It's a funny easter egg in the manga as well.