Mard Geer Tartaros

"It shall begin soon... Darkness will pour forth from the doors of hell... a darkness to swallow all the world's light."

- Mard Geer Tartarus to E.N.D.

Mard Geer was the main antagonist of Tartarus Arc in the manga/anime, Fairy Tail. He was an Etherious of the Dark Guild Tartarus and was E.N.D.'s right-hand man. Mard was known as the "Underworld King".

Appearance
Mard Geer is tall, lean and has the appearance of a young man. Often seen wearing a smirk, Mard's black hair is long and wavy, reaching his shoulders even whilst the majority is tied up in a very large ponytail. Additionally, his messy bangs all but obscure his dark, slanted eyes.[1]

For clothing, Mard's dons a long, black jacket trimmed with a light-colored flame pattern; the lapels are a matching lighter color as well. The cuffs of his jacket are rolled up, revealing a light-colored inside, which contrasts the black inside of his jacket, and have a black line cutting through the edge of the fabric. The jacket itself is tattered and splits into four torn fabric segments at the tail. Beneath the jacket, Mard wears a frilly black v-necked shirt, lined in a lighter color, that closes down the middle and is adorned with a buckle just below his clavicle; just below this is a piece of fabric that Mard keeps over this shirt but under his jacket, that circles the majority of the lower half of his torso. The rest of his attire is simple, consisting of light-colored pants that lay lazily over the top of rather plain black boots and have, on each leg, a seam running down the middle, as well as two pairs of buckles that form an X on the thigh and lower calf.[1] However, the buckles on each thigh later disappear, leaving only the ones on each calf.[2] 

Personality
Often seen smirking, Mard is a cool, collected, yet arrogant man who plays himself off as being extremely intelligent; he quite regularly refers to himself in the third person.[3] Also, much like the rest of his kind, Mard belittles humans,[4] and thinks of them as nothing more than insects. Indeed, he finds the mere thought of letting a human live when given the chance to kill them a tragedy, and is not above torturing his subordinates when they cause him any sort of inconvenience (ironically, not much later, he begins to understand, after fighting Sting and Rogue, that toying with humans can be quite enjoyable, as he ultimately finds their ignorance and belief in things such as hope incredibly amusing).[5] Additionally, Mard takes great pride in being one of Zeref's Etherious; he also has a habit of referring to Cube as his "garden", and appears to love it enough to make Fairy Tail pay for bringing harm to it, even though he noted that ultimately, it didn't matter in the slightest.[6] However, after many outsiders intruded and Cube was destroyed, Mard began to feel, for the first time in years, anger, an emotion he expressed himself to have forgotten long ago.[7]

Mard is also rather intolerant of human emotions, having decided to kill his for the sake of putting his intellectual side first. He also cares a great deal for E.N.D.'s safety whilst in book form, setting his tome down before proceeding to unleash his fury against Natsu and the Twin Dragons, as he was unsure of what rage would do to him.[8] When throwing away his calm nature, Mard's arrogance grows leaps and bounds, as after he emerged unscathed from a full-scale assault from his Dragon Slayer opponents, he merely sat upon his throne and goaded them by saying that he has yet to use his Etherious Form, as well as that they should give up.[9] Though when variables that he did not predict come into his equation, such as the Gray receiving Silver's Ice Devil Slayer powers, even he can lose his composure and exhibit shock and awe.[10]

Curse and Abilities
Thorn Curse (荊の呪法 Ibara no Jūhō): A Curse of Mard's which allows him to create a series of thorny rose vines, the Curse can be used as a means of "punishment" for those who cause inconvenience to Mard, as the vines wrap around the target extremely tight, digging the thorns rather deep into their body. Furthermore, through this Curse Mard is able to use his Curse Power in various ways, such as a thorn-imbibed shield or rose-shaped explosion, and grow flowers to attack opponents.

Memento Mori (メメント・モリ Memento Mori): Mard is able to produce a dark paralytic mist around the target that envelopes them, creating a massive beam of dark spirits that reaches towards the sky. Known as the ultimate Curse and the Memory of Death, this Curse was created to destroy the immortal being Zeref as the victims of this Curse are no longer alive nor dead, but are simply erased, becoming nothing for eternity. However, to some degree, it appears that Devil Slayers have the ability to resist the effects of this Curse, however the majority of their body turns black and has the appearance being dead.