The villain may want power, he may just be a psychopath with a love for showmanship, or he may have some other motive that he's not gonna reveal because it's only the 22nd chapter. Either way, this is one of the more unique (isekais? Time traveling?) manga I've read so I will trudge through the harem, the ecchi, and the suspension of disbelief for most of the magic tricks. And to be fair, the tricks are very entertaining.