To make this easier, unlock Unlimited Hakumen (you can buy in the Galley for 3000$). Choose Iron Tager as the second player and harm Hakumen with two or three command grabs, so the Overdrive last longer, depletes Tager barrier gauge, when Tager is in Danger state, Use A+B+C+D to activate Overdrive, and instanly do →↘↓↙←→ C (max. held) + ←↙↓↘→ C + 5C. Remember it has to be a true combo.