Complex sentence: However, he is also naive and inexperienced, becoming ignorant of the kingdom's decline as he is being influenced by the power-hungry Prime Minister, becoming his mere figurehead, and unaware that he is actually contributing to the Empire's collapse.
Split into simpler sentences: However, he is also naive and inexperienced, and is ignorant of the kingdom's decline as he is being influenced by the power-hungry Prime Minister. He is in effect a mere figurehead, and is unaware that his actions are actually contributing to the Empire's collapse.