Marx Soul

Marx Soul is a powerful, zombified creature that is made from the paralyzed body of Marx, and all of the parts of the powerful Nova. After Marx is beaten by Kirby and crashes into Nova, he and Nova are both caught in an explosion and were both thought to be dead. But it is later revealed that Marx came back to life using most of Nova's energy (Nova himself was later revived by Meta Knight, presumably before Marx came back to life). However, Marx Soul seems to be extremely mentally unstable due to the massive energy absorption, and serves as the final impediment of Kirby Super Star Ultra, being fought at the end of The True Arena. He resembles Marx in both strategy and design, with a few fixes and additions throughout as well. As Kirby lands the finishing blow, Marx Soul unearths a piercing scream, slowly splits down the middle, and both halves explode. Marx Soul is supposedly destroyed for good

In CAMEO!
Marx Soul is confirmed to be a Boss in CAMEO!