An immigrant from the King of Fighters series, Leona Heidern has been a playable character in multiple Metal Slug titles since Metal Slug Mobile 4. She appeared as a DLC character in Metal Slug XX, and then later again as a unit in both Metal Slug Defense and Metal Slug Attack.
As an infant, Leona lost her parents in a tragic incident. She became the adopted daughter of Heidern, who included her inside the Ikari Warriors among the Soldiers of Fortune Ralf and Clark, and subsequently oversaw her rigorous military upbringing (sometime before Whip was included in his squad).
Leona has light blue hair in a ponytail and has blue eyes. She wears an army green military jacket that is cut short, exposing her midriff. She also wears matching shorts held by a belt, knee pads, socks, and army boots to go with her outfit.
When her Orochi blood goes haywire, Leona's hair turns red, her eyes have no pupils or irises, and her skin turns pale due to lack of blood.
This taciturn and aloof young woman has found everyday socialization difficult, yet she is a consummate soldier with a committed following amongst her subordinates. In combat, she accomplishes her missions in an efficient manner many describe as “sublime”, annihilating the enemy primarily with a hand dagger bequeathed by her foster father. She is also acquainted with the SPARROWS agent Fio Germi and apparently undertook a mission alongside her and Clark, binding this threesome in a tight bond of camaraderie.
The majority of her minimal off-time each year is spent in the unusual pursuit of “factory touring”, which is rumored to serve as an unusual restorative to her vigor and energy. In the fighting tournaments that she has participated in to fulfill her missions, she is often observed to display an unimaginable fearsomeness whose source and details remain maddeningly obscure...
In Metal Slug XX, Leona is an above-average character, presumably due to her downloadable character status.
Her specific abilities consist of the following:
- She can perform a special melee attack called the Moon Slasher at any time while standing on the ground (by holding the left shoulder + fire + up), dealing about twice as much damage as a grenade (but without requiring any ammo or suffering any cool downs). This technique furthermore erases nearby enemy attacks, but points are not added whilst performing it.
- Increased damage resistance while inside Slugs (can take four hits before getting destroyed, instead of the usual three).
- Gains +20% ammo from weapons drops.
- Gains +20% grenades (12 instead of 10 from the start).
- When she loses a life, she keeps the weapons she was carrying; she does lose them after using a continue, however.
Originally a cameo in the game's POW list, Leona later becomes a purchasable unit alongside Ralf and Clark in a later update. A melee battler, her close and long range attacks is a simple stab, and her special is her exclusive Moon Slasher that is able to destroy enemy projectiles. Unlike her Ikari pals, Leona instantly dies when a Metal Slug Attack runs over her unless she activates her special at the precise moment.
Leona reappears as a pre-acquisition unit, now available in the POW Shop. She's a purely close-range unit with low health. Compared to her MSD counterpart, Leona can take and give more damage, can counter attacks that would've knocked her back, and her special adds an evading dash prior to the usual attack-cancelling Moon Slash. Leona is also given new variants:
- Cat Ears Leona: Leona in a skimpy cat costume; she trades HP for stronger attacks.
- Orochi Leona: Leona gone berserk; her Moon Slasher is her close range and an explosive V-Slasher is her special attack.
- Leona ver. Heroines: Leona wearing her military outfit from SNK Heronies: Tag Team Frenzy. She fights like her Orochi counterpart but with evasion and a stronger special.
- "Silent Soldier" Leona: Leona wearing her matching outfit from The King of Fighters XIV. She is somehow similar to her Heroines variant in terms of combat but more powerful.
- "Steel Bodyguard" Leona: Leona wearing her a similar outfit from The King of Fighters '96. Functions similarly to her Silent Soldier variant but more powerful.
She first appears in the Extra Ops "Zombie Parade", where she dresses up in a cat costume in order to infiltrate a zombie group being controlled by a Big John. She follows two zombie scientists, which take her to Big John, where she destroys it.
She later appears in the Extra Ops "Blood Runaway", where she is talking with Heidern. When he becomes grievously wounded by a grenade, she believes he has been killed, and her ensuing grief causes her Orochi blood to activate, destroying everything in her path. She returns to normal upon hearing from Ralf that he is still alive, and leaves to get the medical team.
Leona later finds herself in another world with Kelly where they encounter apparitions of Marco and Eri. The apparitions become hostile, which Leona simply takes as an exercise, much to Kelly's surprise. After defeating the pair, they decide to explore further but an unknown entity puts them to sleep, dragging them into the world of Heroines.
Leona eventually returns to her own world and works with Victoria in rescuing stranded Regular Army personnel on an island full of zombies.
Alongside Ralf, Leona accompanies Rumi Aikawa as part of a training exercise. Rumi's clumsiness ends up leading them into the Rebel Army led by Abigail in which they discover the Rebel Army were transporting children, but to protect them from heavy snowfall. She and Ralf play alongside the children in a snowball fight, forgetting about their original objective.
- Leona originally appeared in the King of Fighters series. In every team-based game she has participated in so far she partners with Ralf and Clark.
- She is currently the only playable character in a Metal Slug game to appear as "downloadable content" (purchased at $0.99). In the PlayStation 4 and Steam versions of Metal Slug XX, Leona is available right from the start.
- By holding the Up + Special buttons and either spamming both or quickly alternating the fire and grenade buttons, Leona can perform her Moon Slasher multiple times without waiting for her animation to end.
- In the PSP, PlayStation 4, and Steam versions of Metal Slug XX, Leona's death scream is based from the early King of Fighters games (which are later used in Metal Slug Defense and Metal Slug Attack). Leona uses a different voice in the Xbox 360 and Xbox One versions.
- If performed correctly, her Moon Slasher can cut through most enemy attacks - cancelling them no matter how powerful. The same holds true in Metal Slug XX, Metal Slug Defense, and Metal Slug Attack.
- Unlike other characters, Leona's hair does not retain its color if she's burned - rather, her whole body is charred.
- The Cat-Ears Leona from Metal Slug Attack is an available costume in SNK Heroines: Tag Team Frenzy.
- Leona's death sound in Metal Slug XX (Xbox 360/Xbox One)