As a series of rich, story-heavy sci-fi games with thorough worldbuilding and entire novels of backstory, the Halo franchise is a more-than-suitable candidate to transition to television, and its Paramount+ series is expected in 2022. So far, the scope of the series is unknown, only that it focuses on the Human-Covenant War that dominates most of the Halo storyline.
With such a broad premise, the show could choose to adapt any number of storylines from either the backstory and expanded universe, or the stories told by the games themselves. With so many to choose from, there are nonetheless some fan-favorite storylines that more than merit inclusion.
10 The Battle Of Sigma Octanus IV And The Keyes Loop
Captain Jacob Keyes is a minor ally of the player character in the first Halo game, and a major player in the series' backstory. One of his most notable achievements is a tactic known as 'the Keyes Loop'.
During the war, Keyes's ship ends up unexpectedly engaged by four Covenant ships. Despite even facing one Covenant ship alone being considered effective suicide, Keyes makes clever use of planetary orbit, emergency thrusters, and a nuclear weapon to destroy three of them and force the fourth to retreat. It is an iconic moment of the war, and one that sets Keyes up for his future role as the Commander of the expedition to the titular Halo.
9 Cortana And Master Chief's First Meeting
The relationship between the AI Cortana and Master Chief John-117 is at the core of the Halo franchise, with the two occupying most of the game's screentime, and providing the series with an emotional connection right at its heart.
Their first meeting is both necessary to show the depth of their relationship and a dazzling action setpiece in its own right. Testing John's new armor and their joint capabilities, the two are forced into a politically charged test run by an enemy of the SPARTAN program, where they are forced to survive squads of marines, mines, machine guns, and an airstrike.
8 First Contact Between The Humans And Covenant
If the show attempts to show the full Human-Covenant war, a storyline covering first contact would be essential. After sporadic piracy between the two civilizations leads to a firefight, reinforcements from both sides eventually agree to a seemingly peaceful meeting to negotiate.
This inevitably sours, causing another fight to break out, and ultimately forms part of the reason the Covenant declares a religious war against humanity with the aim of total genocide. Starting with this relatively innocuous first contact could allow the series to open slowly, before showing off the full force of the Covenant, and the direness of humanity's predicament.
7 The Rise, Fall, And Rebirth Of Thel 'Vadam
Introduced as one of the protagonists of Halo 2, Arbiter Thel 'Vadam is initially a loyal member of the Covenant and one of their leading admirals, who is punished severely for failing to stop Master Chief in the original Halo. From here, he is reborn as the Arbiter, an Elite operative who undertakes suicide missions for the Covenant, before being betrayed by the Prophets.
The series could expand on Vadam's role, showing him in his rise as one of the Covenant's most prominent admirals, before his inevitable fall. This could show more of the complexities of the Covenant other than just "hostile aliens", and establish 'Vadam as sympathetic well before he becomes significant to the story of the games.
6 Recruiting The SPARTAN-IIIs
In Halo, the SPARTAN-IIs are the pinnacle of human military achievement, being supersoldiers trained from a young age, with the finest equipment, and surgically augmented to be nearly unstoppable in the field of combat. By contrast, SPARTAN-IIIs are war orphans who were given training and high-class equipment, designed to run suicide missions and cause disproportionate deaths to the Covenant before expiring.
As one of the darkest pieces of the series, exploring the origins of the SPARTAN-IIIs could show the darker side of the UNSC that the earlier games only briefly touch on, and further reinforce just how desperate humanity is in their war.
5 The Menace Of The Flood
The complete opposite end of the war to first contact, the threat of the Flood is the overarching threat of the original Halo trilogy. A corrupting parasite that seeks to overrun the entire galaxy and everybody within it, the Flood eventually forces humanity to cooperate with former foes in the Covenant and eclipse the Covenant themselves as a threat.
As the main thrust of the storyline of three of the most beloved games in the franchise, it seems likely that the Flood will be included in some form, but if the series runs far enough to show them in all their glory, fans would be delighted.
4 The Long Night Of Solace
The Fall of Reach itself is likely to be a storyline in the show, as one of the most iconic parts of Halo's backstory, but within itself, there are several actions that could qualify as entire storylines in and of themselves. One of them is Operation: UPPERCUT from the Halo: Reach level 'Long Night of Solace'.
With Reach besieged by a single Covenant Supercarrier and a direct military assault having failed, SPARTAN Noble Team organise a daring raid, infiltrating with a makeshift bomb after a tense space battle. Ultimately, SPARTAN Jorge sacrifices himself to detonate the bomb, and all is for naught as a massive Covenant armada arrives just as the Supercarrier is destroyed. It is one of Halo's most tense, shocking, and heartbreaking moments, and deserves to be brought to life.
3 The Training Of The SPARTAN-IIs
Developing the living weapons known as SPARTAN-IIs began from a young age, with the most genetically viable candidates being abducted from their homes as children, and forced into brutal training that included live weapons, indoctrination, and impossibly harsh survival training.
Seeing how the SPARTANs were formed is essential for understanding their unique psyches, and especially the character of John-117, the protagonist of the games. Due to happening years before the war, it is unlikely to be shown initially in the series, but as flashbacks, it is almost a necessity to truly explore many of the characters.
2 The Great Schism
A major plot point in Halo 2 is the political maneuvering within the Covenant that sees the honorable Elite warriors replaced and supplanted by the savage Brutes, before a shocking betrayal has the former murdered en masse by the latter, causing all-out civil war.
As one of the series's most shocking twists, instrumental in the downfall of the Covenant, and a necessary part of Arbiter Thel 'Vadam's development, the Great Schism is an iconic part of Halo's story.
1 The Fall Of Reach
With enough moments of heroism, valor, and despair to fill an entire show in itself, it seems almost impossible that the show will not adapt the Fall of Reach in some way. Humanity's foremost military outpost and one of the best-defended planets in the galaxy, the battle over the planet forms the key parts of Halo: Reach and the backstory novel The Fall of Reach.
As one of the bloodiest, most desperate, and tragic battles in the franchise, the Fall of Reach continues to supplant even the Battle of Earth in the eyes of fans as the central piece of Halo lore, and to many fans, it would be unthinkable to leave it un-adapted.