Martel

Martel (also spelled Marta in the 2003 anime English dub and the Polish sub Hyper version of said anime) was a human chimera combined with a snake. She was one of Greed's henchmen. She had the ability to stretch and twist her limbs, as well as her neck.

Background
It is implied in the 2003 anime that Martel was a soldier who unknowingly started the Ishval Civil War before being imprisoned in Laboratory 5; though the manga states that she was critically wounded by a land mine in the recent Southern border war with Aerugo. She stepped on a mine and was taken to an army lab. While in the lab, she was combined with a snake. She escaped soon after, along with her friends Roa and Dolcetto. Martel told Alphonse that the mine blew her in half, and gained a new body after she had her half body combined with a snake.

Manga
In the manga, Martel is first encountered in Dublith. She aids significantly in the capture of Alphonse Elric by getting inside his armor and stretching her limbs to impede his movements. In the raid on Devil's Nest, she stays in Al's armor and survives the massacre. However, when Greed, Martel, Roa, Dolcetto and Al try to escape through the sewer system, Führer King Bradley arrives to impede their efforts. Roa and Dolcetto are killed almost immediately and Greed is defeated by Bradley. When Martel tries to kill the Führer for the murder of her friends, Bradley stabs her through Al's armor, killing her instantly. Martel's blood upon her death affected Al's blood seal, which allowed him to recover his memories of The Gate, and eventually it would allow him to be able to perform alchemy without a transmutation circle. His older brother Edward, Major Alex Louis Armstrong and the military had her corpse taken out of Al before he regained consciousness, as it would traumatize him if he noticed.

2003 anime
In this anime, Martel's role is slightly bigger. She first appeared in the Laboratory 5 arc, where after the explosion caused by Barry the Chopper deactivated the electronic lock on her cell door, she and the other chimera escape and join up with Greed, who had also just escaped.

Later in the story, similar to the manga and 2009 anime, she worked towards capturing Al at Greed's command, so he could understand the secret to the armor boy's immortality, due to the weaknesses that his Homunculus body has. Martel survives the Devil's Nest attack due to the Führer not being present in the Devil Nest's raid in the 2003 anime and she follows the Elrics to eastern Amestris to seek revenge on the ones responsible for the deaths of Greed and her fellow chimera namely Solf J. Kimblee who betrayed their group, along with the other Homunculi and the State Military. Martel also mentions to Ed that while he was the one who finished off Greed, she doesn't blame him since Greed would have preferred to die at Ed's hands instead of being sealed away again. When they travel through Ishval, Martel reveals to the Elrics that Amestris' claims of how an Ishvalan child's death that started the Ishval Civil War was a lie, and that she and her fellow chimera were part of a Black Ops team to stir up an uprising in Ishval which started the war before they were captured and turned into chimera to silence them.

When the Elrics arrive at a nearby military base, Martel was forced to remain inside Al's armor due to her status as a wanted fugitive, until she spots Kimblee and attacks him, only to be nearly killed by him, but was saved by Al, allowing her to escape in the confusion. While on the run, Martel spies on the Führer and Kimblee in a secret meeting as they plan to destroy Reole. When trying to attack the Führer, Martel finds out that Bradley is actually a Homunculus and tries to escape. Bradley follows and kills her in the same way as the manga and 2009 anime, but not before she tells Al the truth about Bradley.

Martel also implied to the Elrics after arriving in Ishval that while she was imprisoned in the Laboratory for fourteen years, her body's appearance never aged and that she is actually older than she looks. Martel also claims that she's old enough to be Ed and Al's mother, implying she's in her late 30's.

Trivia

 * Like Roa and Dolcetto, Martel is a brand of fine liquor.
 * Martel's tattoo appears magenta in the 2003 anime while in the second series, it's green.
 * Another minor change to Martel in the second series is her eye color being changed from green to blue.
 * In both series, Martel was killed by King Bradley while inside Al's armor (the only difference is that the 2003 series, she willingly went inside to hide from him, while the 2009 anime shows her being forced to stay inside, both due to Roa and Dolcetto's orders and because Al hoped to protect her from Bradley but also to try to keep her from doing something he himself would have regretted-- take another's life.)
 * The 2003 anime shows a scene of her attempting to fight Bradley because she blames him for the deaths of her friends (also possibly because Bones studio wanted to redress that she didn't get to fight him in the manga), though she never stood a chance in either version.
 * Although her age isn't specified, in the 2003 anime, she says "I'm actually old enough to be your [Edward's] mom." This could mean she was, at youngest, in her early thirties, although she could be and is most likely much older.