The Hidden Temple Key
is a unique item needed to open the door where you can find Lady Butterfly
in Hirata Estate. To get this item, you have to do the following:
Start from the Bamboo Thicket Sculptor’s Idol. Make your way up along the path. Beware of enemies, especially the archers on the high ground. You can sneak past some enemies along the main path by grappling to the first ledge to the left and to the next branch by the stream. You can stealth kill one of the two swordsmen hiding there then work your way in dealing with the others in the high ground.
If possible, try to lure the foot soldiers to a spot away from the archers’ line of sight. Take your time picking them off individually until the path’s clear. Approach the bridge to see a large, club-wielding enemy and two shield-bearers. To make your job easier, get in the line of sight of the large enemy and lure him out of the bridge, away from the shield-bearers. That way, you can isolate him and take him out.
After getting rid of him, equip your Shinobi Axe and engage the shield-bearers. Continue to the yard surrounded by burning buildings and you should see a lone, bulky, dying samurai that’s actually your father figure. Talk to him to receive the Hidden Temple Key.
The yard will be totally engulfed in flames so you can either escape by using your Homeward Bound Idol or hook to the grappling point of the tower outside the wall.