Personally, I'm running Darui, Sasuke and Guy.

Guy gives attack boost and leech, so I don't need to make my main use the Anbu passive to sustain. Furthermore, his passive doesn't discriminate between Leaf and non-Leaf characters.

Darui's auto barrier gives him a second attack, plus he has a 10 combo chase.

Sasuke has a barrier and a 10 combo chase. And he can be promoted to 5 stars.

The procedure is actually very simple: Use Darui's, Guy's and your own mysteries as much as possible throughout. Initialise Sasuke's barrier only at the tail end of round 3 when Darui has already launched his second attack, then finish using his mystery as late as possible in round 5.