Zeku is the final character to join the Street Fighter V roster in season 2. He was revealed at the SouthEast Asia Majors 2017, a major fighting game event held in Singapore.
Zeku will be available for purchase on October 24 and he completes the season lineup of characters that have never been a playable character in a Street Fighter game before. Well, Akuma doesn't count.
Zeku isn't a brand new character in the Street Fighter lore. Zeku first appeared as a non-playable character in Street Fighter Alpha 2 as Guy's master during his story mode. It is said that he is the one that taught Guy the art of Bashinryu.
Based on the gameplay trailer, he does resemble Guy's move sets. But what's interesting is his ability to change his whole appearance and switch into a younger self. That younger self has access to new move sets and greatly resembles Strider Hiryu, from the Strider franchise. No details of how his V-Trigger works or even his V-Skill but the ability to change from Zaku's old self to a younger version is a concept that makes him an interesting addition to Street Fighter V's growing roster.