I read a sci-fi novel in the past 20 years. It was about Earth fighting against an alien armada. There was some bickering among the humans, but one of the main characters was an Asian industrialist who was just a brain living in a robotic body. I also remember an emperor who had multiple personalities implanted at birth that was supposed to make him a better leader but just made him really odd. A key element was they recruited a giant, living seaweed-like alien with mind-control powers to stop an enemy fleet so the humans could kill them. They had to basically suck the seaweed into a giant colony ship to get it off its home planet and up to the space battle. Definitely in the military sci-fi genre as the seaweed took a military rank to fit in with the humans. English, USA publisher likely.