After all said and done, here is my candidate. Hope you like him. :)

Name: Jones S. Ban

Sin: Envy

Powers and Abilities: Jones S. Ban has eaten the Tomi Tomi no Mi, which grants him the power to steal his opponents luck and add it to his own through certain physical mediums, becoming virtual powerhouse in physical confrontations. Aside of that, he is a gifted swordsman in great physical shape, versed both in traditional military techniques and unorthodox forms of fighting. Ban is a shrewd individual, with a knack for playing dirty. He is also capable of using both Bosushoku and Kenboshoku Haki.

History: Being the son of washed-out middle class people, Ban had lived his childhood in the slums of Asha underbelly, engaging in thuggish activities to make ends meet. Despite his lowly social status, he had the ambition to pursue a military career, making a name for himself and escape from the squalor of his poverty. After years of saving money, he finally got enough to be enrolled in Royal Military Academy. Teachers were impressed of his martial talent and great love for fighting; however, the same belligerent personality ultimately undid Ban military’s career, as he constantly picked up fights with classmen of higher social status. After his rejection, he put the skills he learned in Asha underground fight circuits, obtaining a name and a reputation and some money. After winning a particularly prized match, he was awarded with the Tomi Tomi no Mi by a mysterious individual. Gifted with power over fate, Ban decided to make a name as mercenary and duelist, finally obtaining the recognition he believes he deserves.

Why is he Envy?: Envy is defined principally as a desire to inflict others misfortune and pain, to rob them of certain (perceived) superior qualities. With the usage of his Fruit, Ban can make moot any advantage his opponents may have against him, no matter how powerful they are by comparison. This makes Ban possibly the deadliest Sin to face one-o-one, a weapon his kingdom may use to even the odds against many of the monsters in the New World. It also fits with Ban’s abrasive and competitive streak. Ban shares a strong hatred toward those privileged which flaunt their power and status, and loves to knock them down.

Weaknesses: Tomi Tomi no Mi requires a physical contact between Ban and his opponent: if the latter is smart and fast enough, he can avoid the Fruit power. The fortune Ban absorb through his Fruit is not taken forever, just borrowed, and will return to the user if enough time passes or Ban “consumes it” with many favorable things happening to him. While Ban has the reputation of a notorious cheater, that is, he actually has a sense of honor: if provoked on his swords skills, he would refrain to use this advantage and fight fair and square.

I actually really like the character! The ability and drawbacks are pretty nice, and makes me think he's a fragile speedster. However, you haven't really said why he is Envy, you just said he is Envious. So, not approving.

Also, a guy who steals "things" and's named Ban? :V

Yes, Ban was an happy choice of mine. Still, I will explain better why Ban is Envy.

Envy: While Envy is more moderly associated with a "perverse" form of emulation nowadays, Envy is classically depicted as the "very opposite" of generosity (look no further than Dante's Purgatorio as an example), a burning hatred against the good fortune of others, a desire of bringing them down. Ban is Envy because his powers and modus operandi are all centered on this predicament: he steals luck from other people, making those who are rich and powerful miserable. As a duelist, he routinesly defeates everyone who belittle him by robbing them of their good fortune and laughing as they lay down humiliated. The Goverment has discovered the nature of that power of his, and want to use it to its advantage: when it is required to dispatch few but incredibly powerful individuals, even above the other Sins in terms of might (and the New World holds plenty of them), Ban has the necessary tools to deal with them. Ban might not be strongest, toughest or even most skilled fighter, but he is a master of turning his opponents life in a living hell.

Well, it's as I said, that isn't a singular FEAT which stands out, y'feel?

Like, for example. Damon stopped an entire civil war on his own through his anger, not several wars through time. Rika unified many religions at ONCE, not through several processes.

So, it's like, a SINGLE FEAT WHICH STANDS OUT. Not just personality traits and constant actions.

Ok, here is my feat

Why is he Envy: while Ban had already been enjoying quite a fame as a freelance fighter and duelist, he truly came in the Kingdom spotlight only after a rather "unusual" predicament. One night after he had eaten his fruit, when he was sure he had mastered his craft, he returned to the Royal Academy for a sweet vengeance. Knowing that they had to host the strongest of the Sins (Atraxias: got Ash permission on this one), he bought an enormous amount of paint and dripped every wall of the Academy with oscenities.

The Royal Comitee found Ban basically mooning them, challenging his formers masters in a duel while insulting their honor. Being provoked in front a Sins, the strongest fighters the Royal Academy had to offer coul not back down, and sought to teach the rogue swordsman a lesson: however, to their shock, he proved to far from the idiotic bully he fancied himself to be. Ban made a short work of everybody involved, either besting his peers in skills or inflicting them painful misfortune with the power of his fruit.

After the Onslaught, only a man was left standing: Atraxias, Sin of Pride and general of the Royal Army, whose attention was picked by Ban's proficiency and unique luck. The two men pridefully duelled with the best of their abilities in a fierce challenge, Atraxias ultimately winning: however, he was so impressed by the duel that he proposed Ban to the King as the Sin of Envy, the one who sends ruin and bad luck on Asta's enemies. Is it good enough as a backstory?

Oh, I actually like it! Go on :D seems more than good enough!

Here goes nothing, since it appears that Queen is gone:

Name: Valentin Dolohov

Sin: Lust

Abilities: Stealth, swordsmanship and minimal hand-to-hand experience in the form of Okama Kempo makes its appearance in Dolohov's arsenal of skills. He has had to learn to move quickly and strike with infallible accuracy due to his small and rather weak frame, making him a rather skilled assassin. His Devil Fruit is the Tai Tai no Mi, the Body Body Fruit, that allows the user to take complete command over their own body as well as those of others (if Valentin has come into contact with those he wants to control), with his main focus being manipulating his own blood, bones and even flesh to attack his foes with a myriad of grotesque and deadly attacks. When he is fortunate to have come into contact with an enemy, he is capable of reducing a person to a puddle of blood, or turn them into a soldier for whatever cause has caught his attention. Through his fruit, he has increased his body's own state, granting himself biological immortality as well as increased physical attributes to make himself a better fighter. Though he would much rather make love...

History: On the streets of some far away city on some far away island that Valentin couldn't care to remember the name of, a little red haired child was born an urchin, his mother having died and his father having never been in the picture for longer than to plant his seed. He had to sneak and steal food for himself, find places to sleep between trash cans or in people's basements if he was lucky enough. Life for the young, nameless child was rough, until he ran along the path of a pirate woman who didn't like being stolen from. Unfortunately, he hadn't gotten the memo and tried to take her purse. The lady, rather than flaying the child or worse, decided to take him on. She loathed to waste a pretty face, after all. The boy was named and taught the ways of the pirate, as well as the pleasures of the flesh. He was pretty enough to be a girl, so there would most likely be a time where he would be called upon to use these looks to get out of a pinch. Nearing his adulthood, he ate a Devil Fruit his captain had been saving to sell, without realizing just what he had done. With his new power, he came to the realization that there was much more money in hunting pirates than being one. The ship that had been his home for most of his life was painted red in a single night of fumbling around with his abilities, culminating in his coffers being filled to the brim with coin. This hunting went on for years, until he decided to settle in a place he could call his own. He discovered the Kingdom of Asha and noticed a surprising lack of brothels therein. He established one and over a number of years made a network of not only brothels, but entertainment establishments, taverns, restaurants and clothing stores across the empire. It didn't take long for the news of a terrible bounty hunter turned business mogul reached the ears of the rulers of the kingdom, and he was approached to become the sin of Lust.

Why He's Lust: Valentin is, in essence, a very lustful individual. Using the powers of his fruit, he is capable of taking on any number of provocative forms for those he holds as an audience, being able to tickle anyone's fancy due to his ability to change his form at will. Not only that, but he is also capable of taking over an opponent's body and increasing their sex drive so that all they think about is sating their taste for flesh. It also helps that he is in command of all of the most lucrative brothels in the kingdom, with only the lower class brothels belonging to others, and even then most of those are on his payroll in some way or another.

Weaknesses: Valentin has few weaknesses outside of those typical for a Devil Fruit user, namely sea water and Seastone. He also lacks any form of Haki, making him highly susceptible to that specific power. Valentin is biologically immortal, being impervious to disease, poison and aging, however he is capable of being killed in combat, through massive damage to his head or heart. If these methods are not used, he has another, more abstract weakness. He no longer is capable of ingesting regular food, feeding exclusively on the blood, flesh and bone marrow of humans. He can feed on animals to a lesser effect, but he will weaken exponentially when doing so. Due to this, he must feed on humans to sustain himself and if he does not he will die of starvation. Exsanguinating him (removing all the blood from his body), will rapidly increase the rate of starvation as well, as he needs to feed to restore that which he does not have within his body.

Hmmmm, I like him, I think the blood purdle is a bit OP, but his abilities seem solid and worthy enough!

Again, guys, simply being Prideful, Rageful or anything won't just make you into a Sin. While I understand the brothel thing... You have to have a feat or event related to the sinful aspect of yours, so that the King deems you as a Sin based on it.

Disapproved.

Welp. Time to get lusty:

Why He is Lust (cont.): One of Valentin's crowning achievements, and what has truly earned him the title of "Lust", is an event that occurred when he was just building business in his first brothel. A pirate ship and her crew threatened where he had made his home, saying they would raze the entire town to the ground unless tribute was paid. Valentin, fearing the loss of all that he had earned as well as his establishment, volunteered himself to "negotiate" with the pirates. He stepped onto the ship and nary thirty minutes later he was stepping off, a smirk upon his lips and a call for the police being issued. The scene that met them on the ship was one of a rather "mature" rating. All of the crew members seemed to be engaged in a passionate orgy, which Valentin himself admitted he had incited with the power of his Devil Fruit, and they were all too preoccupied with their love-making to take notice of the officials. Once they were all done and sated, however, they were to tired to resist being arrested and taken to jail cells. Not only was he lauded as a hero for this display of his power, but his brothel got more and more business due to a rumor about his "power of love" spreading throughout the town.

Seems... better, an actual feat, okay. I'll approve you, HOWEVER, Dazz had also wanted the Lust seat. So, I'll put it on hold, and wait for his application and decide between the both of you.