Lucario & Melmetal GX is very tough Pokemon and you might even with the whole game without being any Pokemon Knock Out if you play with the right cards.
The reason is that its GX Attack Full Metal Wall reduce 30 Damages from your opponent's Active Pokemon Attack to your Metal Pokemon for the rest of the game. You only need 1 Energy to use this GX . In addition, you can also discard all your oponent's Active Pokemon Energy Cards if you have 1 more Extra Energy attached to Luacario & Melmetal GX.
Full Article at https://ptcg92.blogspot.com/2019/09/lucario-melmetal-gx.html
