Board Thread:Questions and Answers/@comment-29176641-20160720074804/@comment-29176641-20160910145750

Try stacking Dragon, Gross, Valkyrie and Paris if you have it. This should beat it no problem as long as you have enough (I suggest 4) meatshields. If you have Flower Cat (unlocked by dragging the little doorknobs on cat base screen until a message pops up, a meow indicates you're doing it right), that will help a lot as well. Black enemies are strong but are easy to knock back. Bahamut can kill the Shadow Boxer in two hits. Good luck!