Fossa

Fossa is the commander of the 15th division of the Whitebeard Pirates.

Appearance
Fossa is a large and muscular older looking man, with a bald patch on the top of his head, a mustache, a scar running diagonally across his face, and seen smoking a cigar. He has Whitebeard's symbol tattooed on his right biceps, along with three little circles, and he wears a sleeveless jacket, and loose pants tucked inside his boots. He carries his weapon of choice, a katana with a square tsuba, on his left hip, attached to his belt, but was also seen carrying it over his left shoulder with a long strap.

Abilities and Powers
As the commander of the 15th division, Fossa has authority over the lower-ranking subordinates. Fossa seems to be a swordsman, although his exact level of ability remains unknown; however it is presumably quite high. He wields a katana with a square shaped hilt, and was somehow able to engulf the blade in flames. Whether this ability stems from a Devil Fruit or another method is currently unknown. He's very strong, like the other Division Commanders.

Marineford Arc
Fossa first appeared when Whitebeard arrived at Marineford in order to save Ace. He landed on the ice created by Aokiji along with the other Commanders, and started the attack, slashing enemies with his flame-covered sword. He was seen again when Admiral Kizaru kicked Luffy: he assaulted the high-ranking Marine with other Commanders, giving Luffy a chance to carry on. Later, he was shocked at witnessing Squardo stabbing Whitebeard in the chest, and when his captain's quake-attack failed to destroy the siege wall, he commented on the unusual iron composing it. He entered the plaza behind the wall with the others, and was seen fighting alongside his comrades. He later joined Jinbei and other Commanders in protecting Whitebeard's back, and he was the one to reveal that both his captain and Red-hair possessed Haōshoku Haki. He appeared shocked when Whitebeard declared his will to sacrifice himself in order to save his "sons", and incredulously witnessed Admiral Akainu piercing Ace with his magma-fist. When the latter died, he appeared angry, declaring that it couldn't be really happening. When the Blackbeard Pirates killed Whitebeard, he was seen crying, his cigar falling from his mouth for the first time. When Akainu resurfaced from the ground, he commented on his ability to melt the rock, and was among the others, when they faced off the Admiral in order to save Luffy. He was last seen mourning the results of the war along with the other Whitebeard Pirates.

Major Battle

 * Fossa and other Whitebeard Pirates vs. Marines
 * Fossa and other Whitebeard Pirates Commanders vs. Admiral Kizaru
 * Fossa, Whitebeard Pirates and Crocodile vs. Admiral Akainu

Trivia

 * "Fossa" is the Italian word for "Pit", but it could also mean "Grave". It's also the name of an animal species native to Madagascar, the Fossa.
 * Fossa's flame sword is similar to Makugai's electrical sword.