In the Mire Temple level you will come to a circular room with a fire pit in the middle, and a large locked door (which requires a shield crest to unlock), flanked by 2 large mouse statues.
If you hover your blue orb (PS4 controller) over the statues and press L2 / R2 you will light their 2 torches. Now, if you turn around and exit back down the hall to the previous room (don't go through the door if you have already opened it with the shield crest), you will see that at the foot of the stairs to the hallway you have just come out of, there are 2 gold torches on either side of the wall (that are not lit). Hover you blue orb over them and press L2 / R2 and this will ignite them.
Once these 2 torches and the 2 mouse statue torches are lit, then the flame pit from the circular (shield door) room you were in will ignite and the trophy will pop.