Spoilers are ahead for Halo season 2's finale.

Summary

• Halo season 3 must bring in key video game characters to maintain the success achieved in season 2.
• The introduction of new characters tied to the core canon, like an Arbiter, adds depth to the Paramount+ series.
• It would be great to see the Flood Gravemind, Avery Johnson, and others in action in Halo season 3.

Halo season 3 will finally adapt Combat Evolved's story, it can't rest on the sophomore installment's laurels. In fact, to continue the Paramount+ series' success, Halo season 3 needs to introduce several key video game characters. Although the second season still kept Pablo Schreiber's Master Chief out of his Spartan armor for the majority of its episodes, Halo season 2 clearly understood the character — and the narrative — much better.

Characters who were created for the show, including the Dr. Halsey's replacement, James Ackerson (Joseph Morgan), is a pre-existing Halo character, but the show made some adjustments to best suit its story. That said, season 3 can build on this successful approach of combining core canon characters with new ideas.

Not to mention, Halo season 2 killed off a lot of key characters, starting in its Fall of Reach episode. In order to best set the stage for Master Chief’s transition into a lone-wolf soldier, the show began picking off of the Spartan Silver Team. First, Vannak fell to a Needler during episode 4. The following episode, Riz recovered Vannak’s body and was injured severely enough to force her early retirement. Kai, the remaining member of Master Chief’s cohort, sacrificed herself in Halo season 2’s finale by steering a hijacked Covenant cruiser into another Covenant element.

...there’s both more story and more runtime that need filling.

Kai’s actions mean that Master Chief is officially on his own — save for Cortana. But the Silver Team’s Spartans weren’t the only key Halo characters to suffer significant blows during the sophomore outing. Before Vannak went down fighting on Reach, Captain Jacob Keyes (Danny Sapani) lit up a smoke and took out an entire horde of Covenant Jackals so that the civilian evacuation could be completed successfully before the Covenant glassed the planet. The moment is echoed by Laera’s sacrifice in the finale: infected by the Flood she allows Soren and their son Kessler to escape, locking herself inside the facility.

Although it seemed like James Ackerson was as good as dead during the finale, the Spartan-III creator managed to make it out alive with Kessler and Soren. On the other hand, iral Parangosky was taken by the Flood-infected UNSC and ONI personnel who entered the control center. With Ackerson seemingly defecting and Parangosky gone, there’s a bit of a power vacuum within ONI. This means Halo season 3 has good reason to beef up its character roster: there’s both more story and more runtime that need filling.

6 Thel ‘Vadam

The Arbiter Introduced In Halo 2 Needs To Replace Var 'Gatanai

In Halo season 2, Viktor Åkerblom's Covenant commander, Arbiter's iconic brand, the mark of shame. Like Thel 'Vadam, Arbiter Var 'Gatanai is tasked with making up for his own great shame.

Much like Var, Thel realizes the error of the Covenant's ways...

One of the characters who dies in Halo season 2's finale, Var 'Gatanai fails to complete his mission, though he does safely escort Makee to the Sacred Ring. On the Halo, Var and Master Chief duel with energy swords, resulting in the Arbiter's demise. This loss opens the door to a new Arbiter being introduced in Halo season 3. It makes sense for the third outing to include Thel 'Vadam; a crucial figure in the Halo franchise, Thel is also a fan-favorite character. Much like Var, Thel realizes the error of the Covenant's ways, though his actions have a much greater impact. With Makee all in on activating the Halo Array, it would also be pertinent for the show to feature a member of the Covenant who doesn't agree with that life-eradicating decision.

5 Sgt. Johnson

Sergeant Major Avery Junior Johnson Is Halo's Best NPC

One of the greatest non-playable characters of all time, Sergeant Major Avery Junior Johnson makes a memorable debut in Halo: Combat Evolved. Even though the tough-as-nails Marine serves in the core canon's Battle of Reach, he has yet to make an appearance in the Halo TV series. A pivotal player in the Human-Covenant War, Johnson not only aids Master Chief during the conflict at Installation 04, but later helps form an alliance between the Humans and the Elites. If the Flood are coming, viewers will want to see Johnson, and all of his humorous one-liners, in live-action format. Ultimately, Johnson is killed by one of 343 Guilty Sparks schemes. Since the Monitor was introduced in the Halo season 2 finale, Johnson's fate can be tied to the Forerunner creation.

The Gravemind is a powerful example of just how devastating a galaxy-wide infestation can become.

4 Gravemind

The Flood Gravemind Is A Must In Halo Season 3

A so-called "compound intelligence," the Gravemind is the shared consciousness of all the Flood organisms. After the Flood infects all available sentient, intelligent life in a given area, the Flood build a hive and the Gravemind emerges. In the core canon, it manifests as a tentacled, worm-like monster, though it isn't yet clear how the Silver Timeline of the show will tackle the looming threat's onscreen depiction. Already, the show has teased the coming of the Flood Gravemind: Kwan Ha saw the monster in her cave art visions. While the Flood are a huge threat as they are depicted in season 2, the Gravemind is a powerful example of just how devastating a galaxy-wide infestation can become. That said, Halo season 3 needs to feature the Gravemind well before the show's finale.

3 Serin Osman

Former SPARTAN-019 Inherits Parangosky's ONI Role

Formerly Spartan-019, Serin Osman becomes the Commander-in-Chief of the Office of Naval Intelligence (ONI). In the games, she inherits the role from iral Parangosky, but only after the war with the Covenant ends. With the Flood taking out Parangosky in the Halo season 2 finale — and with James Ackerson seemingly defecting from ONI — that leaves a massive void that needs filling. That makes season 3 the perfect time to introduce a spin on the character of Osman, who was a Spartan-II candidate alongside John-117 in the core canon. In other franchise entries, Serin is more or less an extension of Parangosky's will; since the show failed to introduce her before Parangosky's death, it's unclear if that will happen. Still, it would be interesting to see a former Spartan lead ONI.

After the losses suffered in Halo season 2's finale, the Spartan-IVs are an obvious replacement...

2 ODSTs

Halo's Orbital Drop Shock Troopers Should Follow The Spartan-IIIs

The ODSTs — a.k.a. Orbital Drop Shock Troopers — are an elite special operations force in the Halo universe. Part of the UNSC Marine Corps, these "Helljumpers" are headquartered on Mars, though they do spend time training on Reach before the Covenant glass the planet. That said, viewers won't get to see the ODSTs in action on Reach, but the soldiers would still make an exciting addition to Halo season 3. With the second outing introducing Ackerson's Spartan-III program — and with Parangosky eliminating most of them in a ploy to destroy the Halo ring — it seems natural for a new type of soldier to fill the void. While the Spartan-IVs are an obvious replacement, Marines like Talia Perez (Cristina Rodlo) who became Spartan-IIIs could easily wear the ODST armor.

Kwan may have inherited geas (or genesong)...

1 Forerunner Librarian

The Forerunner Could Be Responsible For Kwan's Geas (Genesong)

A brilliant Halo season 3 theory posits the connection between Kwan Ha, The Mother, and the Forerunners. In the Halo season 2 finale, Kwan comes face-to-face (sort of) with the woman from her visions. "I knew you'd find me," the Mother says when she s Kwan telepathically. "I am you," the Mother continues, before calling Kwan a "Protector" and telling her that all of her ancestors are "within." This hints at the fact that Kwan may have inherited geas (or genesong) — "genetic command imposed on an organism or species" (via Halopedia). A lifeform under the influence of geas follows a set of subconscious orders, and only figures like the Forerunner Librarian can create geas. Plus, Dr. Halsey referred to the Forerunner installation on Onyx as a library in an earlier episode.

Even if the Forerunner Librarian isn’t the one to have given Kwan geas, it seems likely that Halo season 3 will introduce more Forerunner lore. Already, the show gave a glimpse of the Forerunner scientist and hinted at the fact that Onyx is a Shield World. Capable of safeguarding sentient life from the destructive Halo ring, the Shield World — and what it holds — would be the perfect way of introducing beings like the Forerunner Librarian if the show doesn’t want to adapt the games one-to-one. On the other hand, at the end of the season 2 finale, Master Chief is clearly seen within the depths of the ring world’s Forerunner structure. Although he’s merely speaking with Monitor, the Spartan’s journey into the abyss means he and Cortana could discover almost anything in Halo season 3.

All 8 episodes of Halo season 2 are now streaming on Paramount+.