Berial

Berial is first encountered as the level boss of Mission 2, then becomes part of the boss rush in Mission 19.

Nero

Mission 2

There are 2 different ways to start with this fight. Aerial Combo is the fastest method but requires awarness to avoid his Punch pattern by not being next to his left hand.

After the Buster you can speed up the process immediately running back to him and continue Aerial Combo Although, it depends on the kind of pattern that he carries on.

It's very important to be consistent at Exceeds to get a consistent cycle.
A safe and standard method of first phase is where Nero spams Combo A till you get him into Vertical Slash Slash loop for Aerial Combo It's slower but reliable.
1st Buster has to be executed when Berial will lose atleast 3 bars of HP. After the face slam slash until he has 3 bars of HP left.
2nd Phase is often RNG regardless of the method that player picks. Standard one keeps him in loop with Vertical Slash Slash loop. Risky one is forcing him to block.
Sometimes, berial chooses to roar or Magma Pillar before doing anything else post Buster recovery. This is a bad pattern and can cost player around 10s and more.
2nd Buster usually depends on his HP state after stunned but, with optimal Aerial Combo cycle it ends with face slam again.

Mission 19

This cycle is always consistent thanks to the DT ability with Max-bet and Showdown
It can also be tricky to get done with inputs where one mistake can get things go south. It's ideal to find better input map to match player's needs.
CS'3ing + EX3-Calibur before Buster will speed up the fight but it's also fine if you forgot to charge CS as it doesn't cost that much of a time for additional CS'3
The cycle while berial downed is Slash → 2 Aerial Slash → EX3-Calibur CS'3 between Aerial Combo when it's available.
If MAX-Act is on point with Calibur then it will only take two CS'3 to kill berial
It's very important to Taunt Cancel at the end for DT to be avaliable on the final Bael encounter

Dante

Distort 3rd hit of your Real Impact against Berial, then Helm Breaker/FullHouse/JC One step left to realign your position and repeat the cycle.
With proper timings, only 2 Real Impact are needed because the optimal way to end this fight is Distorted Just Straight