A King Serves His People
The quest is unlocked after completing the Guardian Graveyard challenge.
"Many are troubled by the recent surge of monster attacks. To allay their fears, King Rhoam would like to show proof of stronger monsters having been slain. Help His Majesty accomplish this goal."
"Learning of the many terrible enemies felled by Hyrule's forces, the people are much more at ease. For their part, the soldiers' admiration of His Majesty has deepened, improving their morale."