Complex sentence: The leading body of the Dark Brotherhood (The Black Hand) is also a key part in the higher quests available; they are undoubtedly a nod towards the infamous group of assassins that killed Franz Ferdinand, and started the first world war.
Split into simpler sentences: The leading body of the Dark Brotherhood (The Black Hand) is also a key part in the higher quests available. They are undoubtedly a nod towards the infamous group of assassins that killed Franz Ferdinand and started the first world war.