WARNING! The Following Article Contains SPOILERS For Justice League: No Justice #2.
Green Arrow is the last hero left on Earth in the latest issue of the Justice League special No Justice. At least, he's the only hero who is in any position to hunt down those responsible for endangering the world. After an invasion that has seen most of Earth's heroes abducted by Brainiac, and the rest put into a vegetative state, no less.
The catastrophe comes as Green Arrow steps into a unique phase of his DC career. Following the events of the "Hard Traveling Hero" storyline, easily one of DC Rebirth's best comic relaunches, the Emerald Archer was offered a seat at the table in The Watchtower. Oliver Queen turned down an open membership in the Justice League, but did agree to act as the team's "secret fist" - a reserve member who could act as a rogue agent, tackling those missions where a hunter's instincts and stealth would prove more useful than a power ring or super strength.
Recent events on DC's Earth Prime have given Green Arrow ample chance to prove his skills and worth to the Justice League. Tracking an energy wave that shorted out multiple satellites (including the entirety of Queen Industries' new satellite network), Oliver Queen discovered that the signal came from a black out zone surrounding an old enemy - Task Force X coordinator Amanda Waller!
Waller and Queen have a long and checkered history in the current DC Comics timeline, comparable to their relationship on the television series Arrow. Neither is personally fond of the other but there is enough professional courtesy left between them to acknowledge that they need one another's help. The two trade information, with Waller explaining that the energy surge was a result of her using every telepath under her influence to rip Brainiac's mind apart and learn why he had kidnapped Earth's heroes.
Green Arrow, in turn, tells Waller that all of Earth's big-name superheroes were knocked into comas shortly after she went off the grid... and that he is literally the last hero on Earth. The grim irony is that by the issue's end, it's clear Green Arrow actually is successful in tracking down the person responsible for leaving the Earth defenseless. The person who opened Earth up to the approaching Omega Titans that threaten to devour all sentient life in the universe.
By killing Braniac - the end result of the overwhelming psychic assault that she directed - Waller also inadvertently activated the cosmic seed on Earth that was meant to summon the Omega Titans. It remains to be seen what The Emerald Archer can do to save the Earth in the absence of the rest of the Justice League but it's unlikely it will involve shooting Waller - no matter how much Oliver Queen would love to do it right now.
Justice League: No Justice #2 is now available from DC Comics.