Nah, lmao, the confusion is totally understandable. The book states this:>How lucky was she that she could realize such a dream through the simple betrayal and sacrifice of the Kingdom?>She wanted to dance.>She wanted to sing.>The joy in her heart was overflowing.>She was truly, truly overjoyed. Her brain felt like it could break from all of this happiness.
I take it Madhouse went "fuck it, why not" and decided to go ahead and let her do that. I'm still laughing about it. The series has its goofy moments, like that one onsen scene, and Renner's true face has already been shown many times, even in this season's intro. This is the moment where she breaks free from everything that stood in her way, it's all paid off, so while it's silly I don't find it strange at all. (Would've preferred they animated the chair force, though.)
Aside from that, all major events from the arc were animated. Thing is, without the books' narration that fleshed out the past and present of the world, I can see why something like Platinum Dragon Lord sweeping in and his connection to the Thirteen Heroes would seem like it came out of the blue. I don't believe the latter had ever been mentioned in the anime so far, while the former has only appeared like two times (one of them being exclusive to the first recap movie, lol). If you haven't read the novels then yeah, you sadly are
being left out of the loop.