Complex sentence: A smaller sub-section of the city can transform into the giant Autobot warrior, Metroplex, but the destruction of his transformation cog in the opening stages of the Battle of Autobot City necessitated that the city be manually transformed to battle station mode.
Split into simpler sentences: A smaller sub-section of the city can transform into the giant Autobot warrior, Metroplex. The destruction of his transformation cog in the opening stages of the Battle of Autobot City necessitated that the city be manually transformed to battle station mode.