My Partner is a Slime!? ~With the Strongest Partner, I'll Use the Strongest Magic to Rise in the World~

Main character Zack has hit rock bottom. His family hates him, and his fiancee called off his engagement. A black object appears before him. It turns out to be Sura, a powerful black slime that speaks human! A great adventure, with the strongest slime! They're aiming to rule the continent!?