Complex sentence: In the video game, Nene's shadow was originally a red version of Blue Dragon, but after absorbing the light spheres that Shu and his friends swallowed, the dragon becomes Chimera (adopting features from all of the other shadows).
Split into simpler sentences: In the video game, Nene's shadow was originally a red version of Blue Dragon. But after absorbing the light spheres that Shu and his friends swallowed, the dragon becomes Chimera (adopting features from all of the other shadows).