HBOWarning! Spoilers for Lanterns Episode 2 below.“So, what’s with Sinestro?”Before the latest episode of Lanterns aired on HBO, it seemed like the DC series would never get around to mentioning that name. Lanterns takes place at a weird point in history for the Green Lantern Corps: so far, we’ve really only seen a much older Hal Jordan (Kyle Chandler) perform his duties as Earth’s one-and-only Lantern, and in 2016, his biggest adventures are already behind him. Still, when we met the “Halogram” — a dewier, more optimistic piece of Hal’s consciousness uploaded into his GL ring in 2006 — most assumed that Lanterns would eventually address whatever ordeal turned him into... well, the surly, salt-and-pepper Hal we’re following in the show’s main timeline.It’s very possible that Sinestro is it. When Hal is briefly incapacitated in Episode 2, Rushville’s sheriff Kerry (Kelly Macdonald) tells him he was calling out Sinestro’s name in his sleep. She also did some Googling about Hal’s former mentor, which she briefly rattles off to Hal once he comes to. Some brief exposition reveals what Green Lantern novices might not already know: Sinestro was once a Lantern, before he attempted a coup and even murdered “one of the bosses,” the Guardians of the Universe. “It also says you were the one who took him down,” Kerry tells Hal. It’s all, of course, a touchy subject that Hal doesn’t want to get into. Even at the very end of the episode, when Hal actually pays a visit to Sinestro (Ulrich Thomsen) himself, we still don’t get much in the way of context. So who exactly is Sinestro, and why is he such a huge point of contention for Hal? (Aside from, y’know, all of the above.)Sinestro’s rise and fall, explainedThe greatest of the Lanterns later became their fiercest villain. | DCIn the comics, Sinestro was widely regarded as the greatest of the Lanterns. The strength of his will and the scope of his intellect were unchallenged among anyone in the Corps, but that supremacy eventually went to his head. His obsession with control made him something of a dictator over his sector, and as his methods for “keeping the peace” grew increasingly violent, he ultimately turned to a dangerous new source of power. He’d go on to become the Lanterns’ fiercest adversary and one of Hal’s most enduring villains, consistently orchestrating the darkest moments of Hal’s tenure with the Lanterns.Hal is one of many up-and-coming Lanterns that Sinestro trained before his fall; just like in Lanterns, he’s also responsible for Sinestro’s defeat. In the comics, they first butt heads when Hal discovers how Sinestro treats the citizens of his home planet, Korugar. Hal’s testimony leads to Sinestro’s expulsion from the Corps, and Sinestro naturally swears revenge against both his former mentee and the organization itself. Further down the line, Sinestro allies with Parallax, a parasitic entity, to combat the Green Lanterns. He becomes the first Yellow Lantern, wielding a ring that harnesses the natural opposite of willpower: fear. He forms a group of rival Lanterns as well, molding them in his own image. He also paves the way for Parallax to graft itself onto Hal’s mind and spirit, which creates big trouble for the Corps and the Guardians.Is Sinestro already a Yellow Lantern in Lanterns?Lanterns doesn’t reveal much about Sinestro’s turn, but the answers may come soon. | HBOLanterns keeps so much about Sinestro close to the chest in Episode 2. Even when he and Hal finally reunite at the end of the episode, he’d rather talk about John Stewart (Aaron Pierre), which leaves a lot to the imagination. Lanterns will hopefully reveal what exactly happened between Sinestro and Hal, but with the help of some context clues, we might already have the gist of it.There’s every chance that Sinestro may have encountered Parallax by the time we meet him in Lanterns, but the series might be taking some liberties with the “coup” he pulls against the Guardians. It’s unlikely that he’s already become the first Yellow Lantern — otherwise, wouldn’t Sheriff Kerry have mentioned it? — or taken any steps to corrupt Hal with the spirit of fear. Instead, Sinestro might have been imprisoned for his tyrannical rule over Korugar. Why he murdered one of the Guardians remains a mystery, however, and we’re probably not getting answers to that any time soon. Still, at least Lanterns seems to be laying the groundwork here; hopefully the series won’t take too long to untangle this messy timeline.Lanterns is streaming on HBO Max.