Seine

Seine is a Wolf Fang (Elf in the anime and later TRPG Replays) Swashbuckler-Border Patrol from the Log Horizon TRPG replay novels and is role-played by Ayasato Keiji. She makes an appearance in the Log Horizon 2 anime along with the other members of Nyanko-tei, and participates in Operation Capture as a member of the Watermaple Consulate Raid Party.

Personality
Seine is the surly but good-hearted type that brandishes her swords for the sake of another and at any obstruction in the way, and is the kind that acts before she talks.

Fallen Guardian arc
Seine and the other members of Nyanko-tei can be seen enjoying the festivities of the Pumpkin Festival, and are also seen fighting monsters, where she draws her sword to kill some monsters with Wolf supporting her.

Later, when the Watermaple Consulate Raid Party is recruiting members, Shironiji drags her along to join in, mentioning that Michitaka had told them about it. Seine demonstrates her accuracy by hitting the targets perfectly, causing her to blush and insist that it wasn't anything special when everyone else applauds her.

When Operation Capture begins, Seine is on Team E with Yuzugo. After Yuzugo uses a Salamander to hit Enbart Nelles, Seine jumps down, using Viper's Thrash and then  to slow him down. She isn't seen again until Akatsuki destroys Byakamaru, which Seine is present to witness. With the murderer defeated and the cursed sword destroyed, other members of Nyanko-tei appear to celebrate their victory. In the after-party, Seine is dressed in her pajamas like the other raid party members, where she gushes over the fact that she had never been to a pajama party before.

Homesteading the Noosphere arc
Along with the other members of Nyanko-tei, Seine aids in the fight against Baglius.

TRPG Replay 1
When her party arrives in Akihabara, they form the guild Nyanko-tei with Seine as the guildmaster.

Trivia

 * Seine shares a voice actress with Chika.
 * In the anime, Seine's race is changed from Wolf Fang to Elf. How this occurred is unknown, as the rough drafts for the opening still depicted her as a Wolf Fang. It is possible that this is merely misinterpration of the concept art of the OP Rough Drafts (most likely the second, as the ears are quite similar).
 * Later TRPG Replay illustrations depict her as an Elf.