Cleeves was a creature from another dimension and was deemed a 'mutant' by his parents. For fear of becoming outcasts in their society, Cleevus was left to die. What his parents did not know was that the baby-child survived and grew stronger overtime. He grew up full of rage and hate and eventually tracked down his parents in his adult life. He murdered them in cold blood. But that was not where Cleevus stopped. His anger caused him to ally himself with a group of rebels whom where set to overthrow the rightfull authorities of his dimension. Although Cleevus and his allies came close, he was eventually captured and banned from his home dimension, to set foot on Earth.
Cleevus was created by Marc Guggenheim and Ardian Syaf and first appeared in X-Men: Gold Vol.2 issue 1 (2017)
Major Story Arcs
With the Brotherhood and in custody with the X-Men
After Cleevus arrived on Earth, he was soon captured by Mesmero and was forced to join the new Brotherhood of Mutants. He and his teammates launched an attack on the United Nations building and eventually kidnapped the mayor of New York City. Due to timely interferance by the X-Men, the Brotherhood was stopped before anyone got seriously hurt. After Cleevus and his team where defeated by the X-Men, he was the only member to be taken into custody by the X-Men, since they are curious about his origin and identity.
While the X-Men seemed to think Cleevus was a relatively harmless creature, he is far from that and is at this moment awaiting his moment to strike and return to his home dimension.