Dragon Hunter synergy

Any attack roll you make against a dragon is a critical hit on a roll of 19 or 20 on the d20.

Synergy : While an ally are in close combat Hunter marks/hex can be trigger by everybody in your team 

All for one: At least 2 ally close combat with dragon : +1.5/party member alive rounded down against Frightfull presence saving throws  

One for all : if an ally are line of sight behind another ally during Breath attack it add +1.5/party member alive rounded down on saving throws