Creature’s responsibility, primarily: bridging tax (5)
I believe the answer is:
troll
'creature's' is the definition.
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for troll that I've seen before include "Folklore monster" , "Dwarfish creature" , "Online annoyance" , "Fish with a moving bait" , "Malignant elf" .)