Complex sentence: Meanwhile, Parvati came out of the cave and asked the Gods that why Lord Agni stole the divine energy, the Gods answered her that they have to keep it safe from Demon Tarakasur.
Split into simpler sentences: Meanwhile, Parvati came out of the cave and asked the Gods why Lord Agni stole the divine energy. The Gods answered her that they had to keep it safe from Demon Tarakasur.