Warning: Spoilers ahead for The Flash season 8 episode, “Armageddon, Part 2.”
A major death in The Flash season 8 irreversibly changes the show. The Flash is no stranger to death — the Arrowverse series has killed off a plethora of characters over the years, heroes and villains alike. However, things take a tragic and personal turn in The Flash’s “Armageddon, Part 2” following Iris West-Allen’s reveal to the Scarlet Speedster.
In “Armageddon, Part 2,” Barry Allen makes valiant attempts to prove his innocence to Despero, an alien who was banished from his planet Kalanor and adopted Earth as his new home. But Barry’s efforts to stop himself from having a mental breakdown are paused briefly when he learns that Joe West, his beloved father-in-law, died six months before. Barry couldn’t remember any of this and was in denial about Joe’s death, which happened offscreen. Inklings of his demise were hinted at in “Armageddon, Part 1,” but now there’s confirmation he’s gone and it changes the trajectory of The Flash.
The reasons for Joe West’s death are not given, but it irrevocably changes The Flash, which is one of the only Arrowverse series to maintain the majority of its original cast members (save for Carlos Valdes’ Cisco Ramon, who left the show in season 7). Prior to The Flash season 8, main character deaths — including Iris, Cisco, and even Barry — have merely been hinted at or didn’t last very long due to the Scarlet Speedster’s time traveling. Joe’s season 8 death marks the longest any original character has been absent within the show’s timeline; it also hints that none of the other characters are safe from potentially dying. Joe’s death will likely not be permanent, but the fact he isn’t at all in the crossover does change the show in that it showcases what life is like without him in it for an extended period of time and also hints at his future on The Flash.
Jesse L. Martin (who plays Joe) was confirmed to return to The Flash in season 8, and he’s still in the the series' opening credits sequence. It’s possible Barry found himself in some sort of parallel universe where a version of Joe did die; conversely, “Armageddon” could reveal reality has been warped somehow to change the timeline’s events. The last fans saw of Joe, he was alive and well, attending Barry and Iris’ vow renewal. While it’s still unclear what may have occurred to kill him off, his death on The Flash could also mean a permanent exit for the character in the future. Joe hasn’t been appearing in every episode of The Flash since season 5, so it’s likely his death is not only a plot point, but a way to give Martin a break.
The fact that Joe is gone so soon is a shock that could inform Barry’s emotional arc for the rest of the crossover. Joe has one of the biggest hearts of all the characters and his influence on Barry’s life has changed him and made him a better person. Not having him around anymore will weigh on The Flash very heavily moving forward, especially as there is still a mystery to solve regarding what happened on the day of and how it led to Joe's untimely and tragic death. Joe’s passing also intrinsically ties in with Barry’s arc and the loss of the former police captain alters how The Flash’s five-episode event sets up the rest of season 8.