The Magister’s Trousers are found within the main Church in Oxeneforda. Enter through a window on the higher floor then climb up into a room above you. Then, use Odin’s Sight to locate the weak part of the chandelier in front of you and shoot it down to destroy the pots that are blocking you from being able to move the barricade. You can now move the barricade and get to the chest.
Tje Magister’s Vambraces can be located within the church in Buckingham. First, you’ll need to collect the key to the church, which is conveniently just outside on the southern side. Alternatively, you can break a window but this will alert any enemies nearby! Once inside, shoot the ladder at the western end to gain access to upper level where you’ll find a chest with the armor inside.
The Magister’s Robes are found within Leah Villa Garrison, north of Oxeneforda. You’ll need to move the barricade on southern building to access the fire pots within, which you’ll need to throw at the barricade blocking entrance into the building to the southwest. Alternatively, you could just use the Incendiary Powder Trap ability to blow up the building’s barricade to save yourself some time.
The Shishi Guard only be acquired during The Saga Stone, as this is when you’ll have access to the main fort. The chest with the gear is located the ground floor of the fort.