Here is the full list of all 18 SAMURAI SHODOWN V SPECIAL achievements.
Play MULTIPLAYER and win 20 times (excluding invite)
Play MULTIPLAYER and win 10 times in a row (excluding invite)
Play MULTIPLAYER and win 5 times (excluding invite)
Clear the game with all four boss characters
Clear the game as Rera
Clear the game as Sogetsu Kazama
Clear the game as Kazuki Kazama
Clear the game as Charlotte
Clear the game as Basara
Clear the game as Jubei Yagyu
Clear the game as Yoshitora Tokugawa
Clear the game as Kyoshiro Senryo
Clear the game as Hanzo Hattori
Clear the game as Galford
Clear the game as Nakoruru
Clear the game as Genjuro Kibagami
Clear the game as Haohmaru
Clear the game as Ukyo Tachibana