The Grave of Maria is a very unusual weapon owned by General Cross Marian. The Grave is literally a massive grave wrapped in chains containing the body of a woman named Maria. She wears an elegant ruffled gown and her face is hidden beneath wrappings and a large ornament or bow fashioned in the likeness of butterfly wings.

General Cross carries her grave with him and uses magic and chains to keep it sealed. Lavi remarks at once point that the incantations Cross is using are forbidden magic, although Cross does not seem phased by it. The corpse of Maria contains her parasitic Innocence, which Cross uses by manipulating her body, thus making her Innocence his own.

Maria's attacks are as follows...

Magdala Curtain: This attack creates an illusion that can hide the target, effectively rendering them invisible. Cross used this ability to keep hidden during his travels and when moving about on the Ark.

Carte Garde: This attack affects the brain of the target, letting the attacker (Maria, or Cross since he is controlling her) control the target's body movements.

what is a fanlisting?

"A fanlisting is simply an online list of fans of a subject, such as a TV show, actor, or musician, that is created by an individual and open for fans from around the world to join. There are no costs, and the only requirements to join a fanlisting are your name and country. They are just a place where you can sign up with other fans. TheFanlistings.org is the original (but not official) web directory for fanlistings, dedicated to uniting the fans."

- From TFL 101: A Guide to TFL.org.

Want to know more? Visit the TFL 101 guide or TheFanlistings.org. You should also check out animefanlistings.com for anime/manga subjects. :)