Complex sentence: In the series "Battle of the Planets", Galactor is re-explained as invaders from the planet Spectra, whose intention is the plundering of all planets that have any kind of valuable or useful resource.
Split into simpler sentences: In the series Battle of the Planets, Galactor is re-explained as invaders from the planet Spectra. Their intention is the plundering of all planets that have any kind of valuable or useful resource.