Warning! Spoilers for DC vs. Vampires #1 by DC Comics
Vampires have taken over the DC Universe, leading Green Lantern Hal Jordan to change into something else entirely. In the first issue of DC vs. Vampires #1, I, Vampire comes to the Hall of Justice to warn the Justice League that vampires have taken down the Legion of Doom. However, when Hal Jordan learns this information, he reveals he's evolved into a vampire himself who can use his powers to hide his proper form.
In DC vs. Vampires #1 by James Tynion IV, Matthew Rosenberg, Otto Schmidt, and Tom Napolitano, Andrew Bennett (aka I, Vampire) makes the trek to the Hall of Justice, nearly bursting into flames to deliver a message to the team. When inside, Bennett informs Green Lantern - the only main Justice Leaguer who is there - that Mary, Queen of Blood has been murdered and that he visited the Legion of Doom in his hunt to find her killer. Instead of finding answers at the villain headquarters, he discovered vampires brutally killed the evil team as well. Bennett quickly realized the killings were the work of vampires. Unfortunately, the horrors didn't end there, as Bennett runs into Lex Luthor, who gives him a vile of his infected blood and demands to be killed. Bennett obliges and escapes.
At the Hall of Justice, Green Lantern and Zan (from the Wonder Twins) both question why they should help a vampire. Green Lantern asks Bennett if anyone saw him or if he told anyone else. The vampire responds that no, he hasn't told anyone else. That's when Hal Jordan wraps a construct around Zan's neck and Bennett's burned body. In a sinister twist, he reveals he's evolved and brutally kills Zan in a blender construct. When Bennett asks how he survived in the sunlight, Hal reveals that since his powers are based on light, his ring can control it and filter it away.
Green Lantern ends up pouring Zan's blood down a drain right as Aquaman arrives on the scene. Aquaman asks Hal if he's seen Green Arrow, who has been missing for days. The comic ends with Batman receiving a letter from Bennett warning him about what's coming while including the vile of Lex Luthor's blood. Alfred tells Batman Bennett said that it "might have just saved the world."
DC vs. Vampires #1 is a wild, bloody Elseworlds story that makes Hal Jordan's Green Lantern a massive traitor. With his vampire powers and the ability to use his Green Lantern ring to stay safe in the sunlight, it's not going to be easy for Batman to figure out that he's not on their side. But they don't call him the World's Greatest Detective for nothing. Stopping the Green Lantern and his vampire army before he infects the rest of the league and wipes out humans altogether will be a challenge, but with Lex Luthor's blood and Bennett's warning, Batman has a fighting chance. DC vs. Vampires #1 is in comic book stores now.