Megastorm is the Duke of Destruction and younger brother to Galvatron, the Emperor of Destruction. In front of his troops he puts on the facade of a tough guy, but when he's in the presence of his big brother, he quickly calms down.
Megastorm secretly wishes to be stronger than Galvatron, but ultimately his goals are far more modest and conservative than his brother's. In his view, Galvatron's ostentatious schemes as not only too risky, they're downright frightening. This further cements his belief that he could do a better job, endlessly plotting to usurp him as Emperor just to satisfy his own ego. Galvatron in return is aware of his younger sibling's attempts at treachery, but looks the other way purely out of brotherly love.
(Source: TFwiki)
