Let's not beat around the bush: Tommen is probably going to die this season.
His death was prophesized in Game of Thrones' fifth season and the Iron Throne has basically become Westeros' version of the Defense Against the Dark Arts position at Hogwarts. That's to say, it's cursed. But the most popular theory as to who will slay the King just so happens to be the most twisted of them all.
Here's why we suspect that by this seasons's end, Cersei will have killed her darling son Tommen:
If you remember from "No One," Cersei had Qyburn's little birds investigate a rumor that turned out to be "much more" than they expected. Book readers immediately suspected that the rumor Qyburn confirmed was of Mad King Aerys' secret stash of wildfire under King's Landing -- something the show helpfully reminded fans of in one of Bran's visions a few episodes back.
As Cersei has made abundantly clear, she has no plans of submitting to the High Sparrow's demands. So rather than dutifully attend her trial (set for the June 26 finale), it's suspected that Cersei will ignite the wildfire to destroy her enemies in one fiery swoop -- something Cersei has repeatedly expressed her desire to do throughout the series' run.
But a recurring theme on Game of Thrones has become the idea of creating weapons you can't control (think the Faith Militant, the Mountain, the White Walkers, etc.) and Cersei is no Mother of Dragons. She likely has no concept of the breadth of destruction she'll sow by following through on this plan, which is why no one should be surprised if the wildfire has some unexpected consequences -- say, like accidentally killing Cersei's son.
If Tommen manages to sneak into the Sept, likely Cersei's main target, without his mother's knowledge, or if the fire spreads out of control to whatever part of the castle Tommen's in, it's highly likely the king will perish in the flames. Because the harder Cersei has fought against Maggy the Frog's prophecy, the more she seems to drive it to fruition. And there could be no more bitter irony than if Cersei's grand fiery gesture to save herself and Tommen from the Faith Militant would be the thing that took Tommen from this world.
However, Cersei isn't the only potential Kingslayer. Check out the other candidates to kill Tommen in the video above.