Summary
While it hasn’t been given an official title or release date yet, Guerrilla Games has confirmed that “Aloy’s next adventure” is currently in development, which is presumablyHorizon 3. Despite the lack of an official subtitle forHorizon 3, it’s entirely possible to speculate on what that subtitle might be by simply taking into consideration where the story is currently at and where it might go, following the events ofHorizon Forbidden West.
The main title of the franchise,Horizon, is a reflection of the series' focus on discovery, exploration, and the unknown. Each game’s subtitle, however, emphasizes something unique to its story, withZero Dawnbeing a direct reference toProject Zero Dawnand also suggesting both an ending and a beginning to something. In a similar way,Horizon Forbidden West’s name refers to the region west of the Sundom, which is considered forbidden because of the unknown dangers within it, while also thematically representing Aloy’s journey into unexplored territory. Now, in light of where the overarching narrative of theHorizonseries is at currently afterForbidden West,Horizon 3’s subtitle is likely to be a double entendre of sorts, just as its predecessors have.

What Horizon 3’s Ideal Subtitle Would Be
Horizon Forbidden Westcould be considered the most important game in the series, as its ending establishes Nemesis, a rogue AI entity, as the true overarching antagonist of the whole story. Created by the Far Zeniths as a failed experiment to digitalize human consciousness, Nemesis became a sentient amalgamation of hatred and destruction, and a threat far beyond anything Aloy has faced so far. As revealed during the final moments ofForbidden West, Nemesisis responsible for driving the Zeniths from their colony and is now on a collision course with Earth to relentlessly destroy all remaining forms of life.
Needless to say, it would make sense forHorizon 3’s subtitle to reference Nemesis in some way.
Fortunately, ifHorizon 3allowed its subtitle to be influenced by the newly-revealed antagonist, it would benefit from the fact that Nemesis is not only the name of the series' overarching enemy, but it can also be used as an indirect reference to something else, thereby honoring the series' tradition of subtitles that carry thematic weight. Specifically, “nemesis” is defined as “the inescapable agent of someone’s or something’s downfall,” so including it in the next game’s subtitle would be both a reference to the antagonist itself and the threat it poses against Earth, both of which are set up to be a big focus ofHorizon 3’s story.
With that considered, “Nemesis Rising” might be the ideal subtitle forHorizon 3, as it would emphasize the importance of Nemesis in the story and its new place in the series' narrative. “Rising” would also be a great way forHorizon 3to bring thingsfull circle for theHorizonseries, as the words “dawn” and “rising” are synonymous with one another. Including “rising” in the subtitle forHorizon 3would also carry positive implications as well, suggesting humanity’s defiance against Nemesis, a new beginning for Earth, and an increased sense of hope in those fighting for the planet’s future.
“Nemesis Rising” might be the ideal subtitle forHorizon 3, as it would emphasize the importance of Nemesis in the story and its new place in the series' narrative.
IfHorizon 3didn’t go with something like “Nemesis Rising” as its subtitle, “New Dawn” would also be a great candidate due to its double-entendre potential. “New Dawn” could suggest both a new perspective brought about by the introduction of Nemesis in the story and a new day for Earth and its inhabitants. Furthermore, “New Dawn” would, just like “Nemesis Rising,” bring theHorizonseries full circle back toZero Dawnin its name alone. Still, something more along the lines of “Nemesis Rising” might better suitHorizon 3’s subtitle, but it’s all just speculation until Guerrilla Games reveals thenext installment in theHorizonseries.