Sai Yukitsugu

Sai Yukitsugu (狭井 雪嗣), known as Itsuki (イツキ) in Gun Gale Online (GGO), is an original Sword Art Online game character and one of the main characters in Sword Art Online: Fatal Bullet. He is one of the most famous and top skilled players in Gun Gale Online and is the leader of the Squadron "Alphard". While he is seemingly a calm and carefree player, Itsuki is secretly on a constant search for something to excite him. This obsession leads to him becoming the main antagonist of Fatal Bullet.

Gun Gale Online
Itsuki has a red- and narrow-eyed avatar with dark grey hair. His outfit prominently features black and white colours, with red seams overall. The inside of the arms of his long-tailed coat are light blue. He carries gun shells on the side and back of his coat. His canon choice of weaponry is a Dragonfall that resembles a real life Dragunov Sniper Rifle as his primary and a Sirius Optical Sub-Machine Gun as his secondary.

Personality
Itsuki is a mysterious character who is never willing to share anything regarding his real personality. Instead of being an open character, he enjoys providing various bits of information about himself, before promptly following up by claiming that he was joking, thus even his Squadron members do not know much about him. Aside from this, he is a skilled leader and a genius player when it comes to laying decoys and traps in GGO.

Towards the end of Fatal Bullet, Itsuki opened up to the Protagonist for the first time, confessing to the boredom he feels, as well as revealing that the only thing in the world that had sparked his heart was them. In the final chapter of the game, he admitted that he had desperately longed for the Protagonist's utmost friendship, to the extent that he did not care for anything that could pose a threat to that, going as far as creating a devious plan that could kill himself, the Protagonist, Kureha, and Zeliska.

Fatal Bullet
Itsuki was first seen by Kureha and the Protagonist in GGO while the latter two were registering for the special update tournament that was occurring that day. Upon noticing and approaching them, he briefly entered into a conversation with the pair, complimenting them on their reputation and willingness to participate in a tournament so soon after joining GGO, respectively, before taking his leave with an expressed wish to see their skills in combat against him during the tournament.

Later, while navigating the tournament dungeon with his companion Python, Itsuki unexpectedly encountered Kureha and the Protagonist again. Although tempted to fight the duo, he decided it would be too easy to defeat them to be worthwhile. Instead, he sent them ahead to handle a difficult enemy deeper within the dungeon, promising to let the two go if they could defeat it. After Kureha and the Protagonist managed to vanquish the monster, Itsuki and Python separated from them at a fork in the path not far ahead.