The phrase "climactic battle" refers to the final and most intense fight or conflict in a story. It is the ultimate showdown that determines the outcome or resolution of the main conflict. Full definition
The Hulk is literally shown in promotional art and trailers for the movie running to battle in the movie's climactic battle in Wakanda. (businessinsider.com)
The game, due in Autumn for PlayStation 4, Xbox One, and PC, will adapt the final climactic battles of the Naruto manga series. (gamesnosh.com)
There wasn't a lot of meat to it, although there rarely is when it comes climactic battle sequences in comic - book properties, but wow, it was fun to watch. (pajiba.com)