Guide to beating the final boss on realistic mode (spoilers obv.)

Get ready to abuse game mechanics!

1. Restart the mission and equip the heal feat and the damage boost when you parry feat.

2. Advance to the room where you need to destroy a few doors with arrows.

3. Destroy all doors but one, and pick up at least 10 arrows, they respawn after a few seconds. (it maxes out at 12 tho)

4. Destroy the door and continue on until the fight with Apollyon, and be careful to not use any arrows.

5. Run around Apollyon repeatedly while killing off the warden and peacekeeper, use the heal when needed but be careful when its on cooldown.

6. Once the heroes are dead, fight Apollyon. This first stage is easy, as long as you don't attack first. Wait for parries and R2 x2 after each one.

7. On the second stage just do the same thing except try not to get backed into a corner. Time revenge for when she is about to hit you, if you have it.

8. Now here is the abusing mechanics part. Remember those arrows you picked up? Get some distance between you and Apolly, and just shoot then at her whenever they get off cooldown. Easy.