This Trophy can only be unlocked during the games' Main Mission 'The Defiled Castle', which can be found in Tokai Region.
After a short while of fighting through the sewers, you naturally come into a section with a male NPC behind a locked door. This is Ryuoshin, and to unlock the trophy you have to give him 30# Dung Balls.
These are awarded primarily from the brown 'Mudmen'/Flan creatures - I did get a Noble Dung Ball from another enemy but the drop rate seems to be very rare.
You will not get 30# from playing the level once, so my advice would be complete it normally and come back when you are a bit over-levelled. You can go upto and past him, spawn a cloud Yokai and then loop back to the starting shrine - Pray here to reset and just keep doing this simple run.
It is a grind, however I was easily able to go from lvl 93 - 101 here during about 3 hrs so it doesn't feel so bad - your mileage may vary dependant on how many Dung Balls drop.
After your 1st Dung Ball gift, you will receive a Gesture.
After 15# I got a Soulstone.
Finally after 30# you will get the Horned Turban Kabuto - and the Bronze Trophy.
Hope your drop rate is better than mine!