After getting the Scorpion or Water Sward, go to the garden tower. There were four levers and a statue in the middle. Climb up on the ladder, then another one, and jump on the back platform. Climb a ladder and run on the wall. Catch a ledge and jump on the floor. There are three paths. Go the middle and find a time portal. Go to the present. Return to the roof and you will see a cracked wall (which Dahaka breaks during the chase). Go in the wall and jump behind it. You see a switch to the left side of you. Use it and climb the altar that appears. Catch the rim above it. Jump on the wall and climb down. Break the designed wall and you will find the Duck Mace. This secondary weapon is almost unbreakable and does almost no damage.