Wonder Woman has utilized a number of different weapons over the years, whether she's fighting against magical forces of evil or more mundane threats. Just as many weapons have been used against her, however, giving certain enemies a power even Wonder Woman could contend with.
There's one new specific weapon though that, while it being relatively new, has appeared in the hands of a number of characters. The God Killer, a sword capable of killing any magical being, has been used by both Wonder Woman and some of DC's deadliest villains in comics and the DC Extended Universe.
What is the God Killer Sword?
The God Killer Sword, despite having an implicit connection to Wonder Woman, didn't actually debut in a Wonder Woman story. Instead, it actually made it's premiere in the pages of Deathstroke. Created by Tony Daniel, James Bonny and Sandu Florea, the sword was given to Deathstroke by the Greek God of blacksmiths and inventions, Hephaestus. The Greek God recruited Deathstroke to use the sword to kill the Titan, Lapetus.
Beyond being a sword powerful enough to fell a deity, the blade also other perks. It can work almost as a homing device to magical locations such as Tartarus. It also creates a telepathic connection between Hephaestus and the wielder. It can absorb and reflect energy, which gave Deathstroke a counter to powerhouses like Superman. It also has a level of sentience, since it defended Slade from an attack by Wonder Woman of it's own accord. Deathstroke eventually gave the blade back to Hephaestus, but it has appeared frequently since then.
The God Killer In Comics
Even though Deathstroke returned the sword, multiple other villains have claimed the blade as theirs. Grail, the twisted daughter of Darkseid and an Amazonian warrior, took the sword while imprisoned by the Amazons underneath Paradise Island. She used it to kill fellow captive Ares and used the blade in her bid to claim control of Theymiscara. However, her rebellion against Hippoluta failed thanks to Wonder Woman and her allies.
However, Diana wasn't able to take the weapon for herself and store it away. Instead, the newly empowered Apex Predator version of Lex Luthor was able to steal it . He gave it to Cheetah, a member of his Legion of Doom and Wonder Woman's frequent nemesis. With it, she has the power and potential to murder any magical being, even the Greek Gods themselves. It elevates how dangerous she is going forward in the battle between justice and doom. She's even used it to kill figures like Aphrodite, draining the world of hope and love.
The God Killer In Film
Just a few years after the sword was created in the comics, the sword made the transition to live-action. It appeared in a prominent place in the live-action Wonder Woman movie. The implicit connection with Hephesteus is less overt, and it's not given to anyone as a gift of the gods. Instead, it had initially been held in a special armor within Themyscria, containing the many gifts the Amazons had gotten over the years from members of the Pantheon.
Diana steals it for herself when she decides to venture into man's world and uses it frequently throughout the battles she ends up involved in across World War I. She uses it frequently in her battles with the German armies, notably in the iconic "No Man's Land" battlefield scene. She even eventually uses it to achieve its namesake, killing Ares during their climatic battle. Eventually, however, she put the blade away and claimed a new sword - the Blade of Athena - as her primary weapon.