Kayaba Akihiko (茅場晶彦, Kayaba Akihiko?), known as Heathcliff (ヒースクリフ, Hīsukurifu?) in Sword Art Online, was the main antagonist of the Aincrad Arc and a supporting character in the Fairy Dance Arc and Alicization Arc. He was the development director and Game Master (GM) of «Sword Art Online», as well as the designer of the «NerveGear»,[3] the Cardinal System,[4] and «The Seed».[4]

As his avatar Heathcliff, Akihiko eventually founded what later became Sword Art Online's strongest guild, the «Knights of the Blood». He was the owner of the first «Unique Skill», named «Holy Sword»,[1] and was considered to be strongest player in-game.[5] He wielded the collective one-handed sword and tower shield called Liberator. He also was able to engage the boss of the 50th Floor in battle for ten minutes by himself, which earned him the title «Man of Legend» (伝説の男, Densetsu no Otoko?).[6] It was also rumored that Heathcliff's hit points (HP) had never reached the yellow zone.