Complex sentence: The are the main antagonist in the 1994 Super Sentai series "Ninja Sentai Kakuranger", they were sealed away 400 years ago by the Kakurangers' ancestors and have now changed their forms to keep up with the times.
Split into simpler sentences: The are the main antagonists in the 1994 Super Sentai series "Ninja Sentai Kakuranger". They were sealed away 400 years ago by the Kakurangers' ancestors and have now changed their forms to keep up with the times.