Despite what was presented to us on screen in Avengers: Infinity War, many fans have doubted the veracity of the death of Loki, strangled before his adoptive brother Thor's eye in the prologue to the Avengers sequel. The opening sequence marked the third time the Marvel God of Mischief has supposedly met his untimely end on screen, alongside 2011's Thor featuring Loki plummeting from the broken Bifrost Bridge in the film's climax and faking his death while facing the Dark Elf Kurse in 2013's Thor: The Dark World.
But while Thor himself believes Loki's demise in Infinity War to be genuine and permanent, the announcement that Tom Hiddleston will return to reprise his star-making role as Loki in a planned live-action miniseries for Disney's premium streaming service, Disney Play, has fueled speculation that the God of Mischief has cheated death yet again.
Yes, he's cheated death twice before, but there was something more visceral and final about the way Thanos squeezed the life from the Asgardian. Why, then, do fans insist he's alive? After all, the Loki series could just as easily take place before or in between his film appearances rather than after Avengers 4's closing act.
Most fan theories observe that, in his final moments, Loki attempts to stab Thanos with his offhand as cited by Reddit user radkarth. In previous appearances, Hiddleston's Loki had used his right hand as his dominant hand with the sole exception prior to Infinity War being The Dark World...when he fakes his own death. It appears that whenever Loki creates a false projection of himself, the doppelgänger is a flipped incarnation, meaning the it favors the opposite hand.
While previous versions of Loki's projected doubles were depicted as intangible, tricking opponents in Thor, The Avengers and Thor: Ragnarok, the version seen in The Dark World was a hard projection as it was able to be held by Kurse. This inconsistency was originally a production oversight: The filmmakers had intended to kill off Loki for good in the 2013 Thor sequel, but after seeing how popular the character was with fans, the decision was reversed, with the character's final fate posing as Odin on the throne of Asgard added during reshoots.
This plot hole may work to the God of Mischief's favor once again, explaining why the Mad Titan was able to grab ahold of Loki after his failed stabbing attempt if it was truly only a false projection that Thanos squeezed the life out of and cradled by his brother after the Black Order's departure. From there, the theory assumes Loki survived both the destruction of the Asgardian spacecraft and Thanos' climactic snap to live to fight another day.
Supporting this theory is Loki's appearance during the Infinity War prologue itself. Pointed out by Reddit user arhyssolacemustdie, all of the other Asgardians present in the opening scene are visibly battle-damaged, including a wounded Thor and Heimdall, while Loki himself is reasonably well-presented given the circumstances. His relatively clean appearance compared to his sweaty, bloodied comrades could do with familiarity; as seen in The Avengers, this is not the first time Loki has interacted with Thanos with the two former allies clearly demonstrating a history but another theory is that his appearance may be due to not being present at all.