Can anyone help me with this?

A lot of books have a huge battle at the end. Narnia for one, The Inheritance Cycle basically has a huge battle at the end of each book. The Mortal Instruments, Reckless by Cornelia Funke , Clockwork Angel, The Great Tree of Avalon, a ton of books have battles at the end. It's completely fine, but if you want it to be directly different perhaps add in strategy rather than straight on battle. And since there's only two humans I think that's a good enough difference anyways.