Blueno

Blueno (ブルーノ, Burūno) is first seen as a bartender in Water 7 and seems to be the most friendly with Franky and Paulie. However, he soon shows his true nature when he, along with the rest of CP9, attacks Paulie and Iceburg for the Pluton blueprints. He is the agent that Robin ran into on the streets in Water 7 while she was with Chopper, as well as the agent whose Devil Fruit powers were used in both attempted assassinations of Iceburg.

While the entire Water 7 CP9 unit gives the first expression of emotionless justice-devoted killing machines, Blueno is the only one to maintain such a façade. While the others -Kaku, Lucci, Kalifa and Jyabura- are shown taking pleasure in fighting, toying with their opponents and so on, Blueno remains calm and collected nearly all the time. As a result, Blueno comes to symbolize the cynical, evil actions of the world government - namely using Nico Robin, blackmailing her through traumas inflicted by the World Government in the first place.

Blueno ate the Doa Doa no Mi (ドアドアの実 Door Door Fruit) which allows him to create doors on any surface. He has even created "air doors", doors in the air itself, which lead to what seems to be another dimension. Blueno is also able to create doors on people, and did so to Luffy's face, causing it to spin like a revolving door. In battle, Blueno also uses his door to move freely through the entire environment, setting himself up for sneak attacks, and even creating small doors wherein he traps his opponents' feet.

Blueno's tekkai seems to be the one of the more powerful ones of the group, and he was the first to reveal any variations of the move. However, despite this advantage, Luffy was able to use his new Gear 2 abilities to defeat him when they fought in Enies Lobby. Lucci stated that Blueno's bartending job has dulled his senses, but it might just be another show of the arrogance of most of the CP9 unit.

After the Buster Call left Enies Lobby in ruins, Blueno turned out to be the savior of CP9, using his Air Door to protect them from the annihilation of the island by the Marine onslaught.

CP9's Personal Report
Blueno is shown using his Devil fruit's ability, Air Door at Enies Lobby while carrying Lucci. Kalifa and Fukurou is also shown at the back of Blueno.

Trivia

 * In the Volume 44 SBS, it was revealed that when Blueno was younger, he loved baseball.
 * He has a bull theme, due to his horn-like hair. He is also referred to as a cow by Luffy numerous times.
 * When invading the Iceburg's mansion he was wearing the bear mask.
 * In a recent Weekly Shonen Jump poll to determine the most popular One Piece characters, Blueno ranked at 81st.