The Students have brought in a raft of new signings during the off-season, with striker Fanteni and midfielder Mashaba the latest arrivals as new coach Antonio Lopez Habas continues his squad overhaul.
Ajax CEO George Comitis confirmed Fanteni's exit during a press conference on Tuesday, saying: "Terror's contract had six months left on it and the player indicated that he would like a new challenge.
"We had an option to renew or agree to his wish to play for a new club. Terror was keen on the move when Wits came knocking, his ambition is to play for Bafana again and he feels that the new challenge will give him the platform to do just that.
"Wits and Ajax have agreed to a transfer fee of R1.5 million.
"We believe that we have enough cover with players like Alcardo (van Graan), Bradley (Grobler), Khama (Billiat) and (George) Akpabio, all capable of filling the central striker's role."