How to break a part of a boss with halberd?

I am new to the game and I already made some bosses, but I could not break any part of a boss with the pj of halberd ... I need help

 

Halberd doesn't have much interrupt skill. There is dragon tail that deals tumble at 100% rate on lvl 10, but you can use impact instead if you want. If you want flinch and stun you can learn martial art skills like smash and bash if you want

 

Dragon Tail's tumble effect does not apply to boss monsters.

 

But the dragon tail works in the bosses to break their parts?

 

Nope.

Halberd itself has no breaking skills in it's own tree since the weapons focus is entirely based upon doing more damage. Which it does really well.

Your best bets for breaking on Halberd consist of either getting Impact from the Magic skill tree or Martial tree skills such as smash, bash, or sonic wave.

You WILL get Impact eventually though. So if you can hold off till then, you can skip out on the Martial skill tree and leave breaking skills to other players you party with.