Goliath is encountered as the level boss of Mission 2 then becomes part of the boss rush in Mission 14 as Mirage Goliath.
It's very important to no damage this fight as part of your optimal route
Because of damage scaling Nero has two breaker set ups: Gerbera x2 to Human and x4 Overture to Devil Hunter. To kill the boss optimally, it has to be during church phase.
Gerbera Cycle Human
Overture Cycle Devil Hunter
When it comes to stunning, this depends on how well you Exceeds with Roulette Spins as the church kill hugely depends on it. Aerial Combo lets you land more hits than Roulette Spins during that state too.
It's pretty much using all of your resources fight although :
New Game+ Churchless cycle
Requires max DT-Gauge so that Shadow and Griffon can tank Goliath attacks. This is the same for NG+ for Nightmare setup. In NG don't forget to grab white orb before V gets teleported out of the room.
New Game example
New Game+ example
This whole fight depends on your execution of JJC. Mission 14 cycle varies due to the position and how Spiral Blades release hits Goliath
Mission 2 Stun example
Mission 14 Mirage cycle
When it comes to Mission 14 you need maxed out PS with Trick Dodge Spiral Blades and Beo Dragon Breaker:
It's good to check the Frequently Asked Questions (FAQ) if you have general questions regarding the bosses.