All three of these are rewards for completing the "Two Graves" side mission that comes the DLC, so you cannot unlock this achievement without first unlocking
Once you have completed the side mission, go back to the Abandoned Village base camp and equip the
Serpent Lash - Godslayer bow and the
Dragon Scales - Legend outfit. Note that both of these are variations on similarly named items that were bundled with the DLC, so be sure that you are equipping these exact items, not their more vanilla counterparts. You learned the Divine Bounty skill at the challenge tomb, so you don't have to do anything at the base camp to make it happen. If you need to check this, press
from the Skills menu at the base camp.
Once you have equipped the bow and outfit and exit the base camp, the achievement will unlock.