Thought I'd post my One Piece OC and see what others think.
Spoilered because of length.

! Name; Gebrinius Hermes
! Epithet; Quicksilver, Felt Hat
! Bounty; 216,000,000 Beli
! Age; 21
! Home Sea; Grand Line
! Affiliations; Quicksilver Pirates
! Appearance; Hermes is a slender and muscular man; standing about 5’11” (180cm). Blue eyes, silver goatee, and silver colored wavy hair that extends a few inches below his shoulders. Hermes has a black fedora hat, which serves as one of his trademarks. His clothing consists of a gray dress shirt, black slacks and black leather dress shoes. Tattooed on his right hand is the symbol for the planet/element Mercury.
! Personality; Hermes is usually a calm and collected person. He tends to be sarcastic to others, if they are annoying him. Hermes has great respect for his crew mates and will do everything possible to keep them from harm if in danger. He is willing to make friends with other pirates if he gets a good vibe from them, but he does understand that they are still his rivals. Hermes hates marines who believe in absolute justice and will show them no mercy. But as a former marine, he is sometimes conflicted about his path.
! History; Hermes was son of a Marine officer and aspired to be just like his dad while growing up. Since his father was a Rear Admiral, Hermes was able to meet several high profile people; including a few Vice-Admirals and some Cipher Pol agents. Hermes went through training to become a marine, starting at age 15. He climbed up the ranks fast, because of his father’s connections and his early skills with Haki and Rokushiki. Hermes eventually achieved the rank of Lieutenant Junior Grade.
! When he was 18, Hermes’ father was killed by a Vice-Admiral while protecting two citizens suspected of aiding a pirate; his father was the only one who knew they were not. Hermes was not told which Vice-Admiral killed his father, and he couldn’t get a straight answer from any of his father’s friends. Hermes trust of the Marines, and the World Government, had been shattered. He rebelled by stealing the Silver-Silver Devil Fruit and running off with a standard marine ship (not the ones used at Marineford) in the middle of the night.
! Jolly Roger; Hermes' Jolly Roger is a silvery skull and cross bones wearing a fedora hat.
! Abilities; Rukoshiki: While his training was not completed, Hermes is quite proficient in some techniques.
! * Finger Pistol (Shigan): Hermes can use the standard Finger Pistol technique, as well as a flicking variation similar to Rob Lucci.

• Shave (Soru): Hermes has mastered the fundamentals of the Shave technique.
• Iron Body (Tekkai): Hermes has mastered the fundamentals of the Iron Body technique.

! Haki: Hermes’ Haki abilities awakened during his time as a Marine. Although he has not fully mastered them, he is still proficient.
! * Kenbunshoku (Color of Observation): Hermes is well versed in this form of Haki and it is the form he uses more.

• Busoshoku (Color of Armaments): Hermes skill in this form is still basic, so he does not use it as often.

! Devil Fruit: Silver-Silver Fruit (Gin Gin no Mi)
The Silver Silver Fruit is a Paramecia class devil fruit with the ability to allow the user to create and manipulate a silvery metallic substance. A side effect of the ability allows the user to detect changes in temperature, atmospheric pressure, and blood pressure.
! * Heavy Metal (ヘビー メタル, Hebī Metaru): The user launches a liquid stream of the substance to infect the enemy and to cause death by heavy metal poisoning.

• Mercury Blade (水銀 ブレード, Suigin Burēdo): The user forms metallic blades on a limb. Capable of inflicting heavy metal poisoning on the person cut. Hermes can use Iron Body to increase strength and sharpness, but is vulnerable to counter attacks if he misses.
• Mirror Armor (ミラー 鎧, Mirā Yoroi): Hermes’ body or part of his body can turn metallic to reflect beam based attacks. It can also be use as a regular mirror.
• Metal Eater (メタル イーター, Metaru Ītā): Hermes can use the substance generated by the fruit’s powers to dissolve most any metal, except for Iron.
• Silver Bullet (銀 銃弾, Gin Jūdan): Hermes uses Finger Pistol to launch metallic bullets by flicking his fingers.
• Heavy Metal Injection (ヘビー メタル 注射, Hebī Metaru Chūsha): Hermes uses the standard Finger Pistol to stab opponents, he then secretes the metallic substance into their body.
• Silver Statue (銀像, Gin-zō): The user covers their body in the metallic substance while using Iron Body to harden themselves. The added hardened substance doubles the damage absorption.

! The only special weakness of the Silver Silver Fruit is that Iron has a resistance to some of its abilities.
Here's a picture of Hermes that a friend drew for me.

Mercury used to be widely used in thermometers, barometers and sphygmomanometers (blood pressure meters).

Well, when you look at how it's spelt, no.
Hebi, as used in Hancock's epithet, is spelt with 蛇.

But the two words sound practically alike.
I guess it could make for a good joke.
And the liquid stream might look like a snake to some.

This thread really caught my eye.

I went through a few pages and found some cool ideas.
In older posts from a few years ago, I've seen Fruit similar to current ones.
There was an aging, crystal, magma, hawk, t-rex, and light Devil Fruit.
Interesting to see these ideas years before they appeared in the series.

I was also hoping to showcase my own.

! Devil Fruit: Silver-Silver Fruit (Gin Gin no Mi)
The Silver-Silver Fruit is a Paramecia class devil fruit with the ability to allow the user to create and manipulate a silvery metallic substance. A side effect of the ability allows the user to detect changes in temperature, atmospheric pressure, and blood pressure.
! * Heavy Metal (ヘビー メタル, Hebī Metaru): The user launches a liquid stream of the substance to infect the enemy and to cause death by heavy metal poisoning.

• Mercury Blade (水銀 ブレード, Suigin Burēdo): The user forms metallic blades on a limb. Capable of inflicting heavy metal poisoning on the person cut. Can use Iron Body(Tekkai) to increase strength and sharpness; but is vulnerable to counter attacks if they misses.
• Mirror Armor (ミラー 鎧, Mirā Yoroi): The user's body or part of their body can turn metallic to reflect beam based attacks. It can also be use as a regular mirror.
• Metal Eater (メタル イーター, Metaru Ītā): The substance can be used to dissolve most any metal; major exception is Iron.
• Silver Bullet (銀 銃弾, Gin Jūdan): Uses Finger Pistol to launch metallic bullets by flicking their fingers.
• Heavy Metal Injection (ヘビー メタル 注射, Hebī Metaru Chūsha): Uses the standard Finger Pistol to stab opponents, he then secretes the metallic substance into their body.
• Silver Statue (銀像, Gin-zō): The user covers their body in the metallic substance while using Iron Body to harden themselves. The added hardened substance doubles the damage absorption.

! The only special weakness of the Silver Silver Fruit is that Iron has a resistance to some of its abilities.
Some abilities are from my OC profile, as my OC can use some Rokushiki.