The anime Super Dragon Ball Heroes is a spin-off series of the universe created by Akira Toriyama, which therefore allows greater freedom as regards the opening towards other timelines, and that for the return of characters coming only from the films dedicated to the brand, as seen in the last episode.
In fact, in SDBH episode 3 Big Bang Mission the antagonists made their appearance Turles and Bojack. Faced with these old enemies, Goku and Vegeta, transformed into Super Saiyan Blue, found themselves surprisingly in difficulty.
Fu's new allies they seem to have gone beyond the limits of the past, becoming more and more powerful, both thanks to their training but also thanks to the energy coming directly from the Tree of the Universe. Turles and Bojack represented the antagonists of the third and ninth Dragon Ball Z movies respectively, and both share particular origins.
Turles, with a face identical to that of Goku, appears on the scene creating the Tree of Power, similarly to what was seen for Fu in previous episodes. Turles had not proven himself capable of defeating Goku and the Z Warriors, but it seems that the scientist managed to separate it from the flow of time to add it to his "villain army".
Bojack, on the other hand, was a very powerful alien-demon, which had as its objective the conquest of the Universe. He was imprisoned on a star by the four Kaioh kings. At the end of the Cell Game, Goku decided to teleport with Cell to the planet of the northern King Kaioh, and after it was destroyed by the Cell explosion, Bojack found himself free. Once on Earth Bojack will be defeated by Gohan.
Although these two villains have been defeated in the past, they now seem totally able to stand up to two Super Saiyan Blue, it is therefore plausible to think that in the future we will see other enemies coming from the past, ready to take revenge for the defeats suffered. We also recall that the title and synopsis of the fourth episode of SDBH have been announced.