While Halo's Master Chief carries the full UNSC designation of "Master Chief Petty Officer John-117", the alien forces of the Covenant have a shorter and far more frightening name for him: "Demon". There are a few different reasons why John-117 has been given the particular name, which is eventually shared with his fellow SPARTANS. Here's why the Covenant refers to Master Chief as Demon, and the likelihood of him receiving the same moniker in the upcoming live-action series.

Coming to Paramount+, the Halo series starring Pablo Schreiber will feature a brand-new story with events taking place in what has been referred to as "The Silver Timeline", serving as a continuity inspired by but set apart from the history and lore established by the Halo videogames and various novels. While this does allow for a greater amount of creative freedom, the core of Halo will still be present if the trailers and promos are any indication: the space-faring forces of humanity fighting against the alien Covenant, their greatest assets being the SPARTAN super-soldier program with John-117 being one of their greatest heroes. However, the games revealed that Master Chief's accomplishments have conversely given him monstrous and near-mythic status amongst the Covenant.

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In the Halo games, Master Chief is almost exclusively referred to by the Covenant as "The Demon", and the weakest aliens known as Grunts actually run in fear when he enters the battlefield. Based upon the pre-existing lore, there are a few reasons why Master Chief is seen as a Demon. Firstly, the Covenant is a highly religious union of alien species, led by Prophets who study and revere artifacts left behind by the ancient Forerunner race (whom they worship as gods). Seeing as how Master Chief has killed multitudes of Covenant in their holy war to eradicate humanity, it makes sense that John-117 would be seen as a monster. Likewise, the name may have also originated following Master Chief's destruction of Installation 4 (the first Halo ring he encountered) as well as his murder of the Prophet of Regret.

Halo Master Chief and Prophet

It should also be noted that other SPARTANS were eventually referred to as Demons as well, becoming a collective name of fear used by the Covenant. While it's unknown whether Master Chief and his fellow SPARTANS will be named as Demons in "The Silver Timeline"perhaps it will be introduced as the series progresses. The Demon name could emerge just like it does in the games following the Prophet of Regret's murder and the destruction of the first Halo ring, though it could also just be used in reference to their feats in battle, depending on how this new timeline transpires.

At any rate, the Covenant's name for Master Chief and the UNSC's SPARTANS proves just how important they are, acting as their primary defense against the Covenant and their crusade to bring about humanity's extinction, seeing them as rival inheritors of the Forerunner technology. John-117 himself has taken out hundreds (if not thousands) of Covenant soldiers in the games and novels. It's no wonder he's seen as the Demon by his enemies, and it would certainly make sense for him to be called as such in the upcoming Halo series as well.

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