Burn Catch-Fire Dc

This is a Universal Monster Rule — a class feature gained through that class's own talent choices, not a feat you pick through normal feat selection.

A creature with the burn special attack deals fire damage in addition to damage dealt on a successful hit in melee. A creature affected by the burn ability must also succeed at a Reflex save or catch fire, taking the listed damage at the start of its turn for an additional 1d4 rounds (DC 10 + 1/2 the attacking creature's racial HD + the attacking creature's Con modifier). A burning creature can attempt a new save as a full-round action. Dropping and rolling on the ground grants a +4 bonus on this save. Creatures that hit the monster with natural weapons or unarmed attacks take fire damage as though hit by the monster's burn attack and must make a Reflex save to avoid catching on fire.