Mera is a prominent superheroine in DC Comics, first appearing in Aquaman #11 (September–October 1963), created by writer Jack Miller and artist Nick Cardy. Initially depicted as the exiled queen of Dimension Aqua, an otherworldly underwater realm, she fled a tyrannical regime and emerged on Earth, where she encountered Aquaman and quickly became his ally and romantic partner. In post-Flashpoint continuity, particularly the New 52 and Rebirth eras, Mera is reestablished as the princess of Xebel—a separatist Atlantean kingdom in an extradimensional penal colony—trained from youth as an elite assassin dispatched to eliminate the King of Atlantis, only to defect upon developing genuine affection for Arthur Curry.

Mera's primary ability is hydrokinesis, granting her precise and powerful control over water, including the formation of durable "hard water" constructs for weapons or shields, manipulation of vast oceanic volumes, and extraction of moisture from targets. Augmented by her Xebellian physiology, she possesses superhuman strength, durability, speed, stamina, and adaptability to extreme underwater pressures, along with the capacity to breathe in both aquatic and terrestrial environments. Her rigorous training in combat, strategy, and leadership complements these powers, establishing her as a formidable warrior capable of contending with threats on par with the Justice League's heaviest hitters.

Throughout her history, Mera has experienced profound personal and political developments, including her marriage to Aquaman, the devastating loss of their infant son to Black Manta, subsequent periods of grief-driven separation, and eventual reconciliation. In modern continuities, she has asserted greater agency, briefly wielding a Red Lantern ring during emotional turmoil, serving on teams such as the Justice League and Aquaman's supporting cast, and navigating Atlantis's internal conflicts as queen. Key arcs, such as those involving rebellions against Corum Rath or alliances against global menaces, have highlighted her evolution into a resilient co-ruler and independent protector of the seas, cementing her status as one of DC's most enduring aquatic heroines.