Lost Souls: 2
Once the path has been fixed, continue forth and smash the door open. Follow the straightforward path until you come across a lost soul behind an angelic web. After freeing the lost soul, continue to the edge for a short scene. Now, jump over the platforms to reach Assiel. A new enemy called the witch will be appear. You have to destroy its shield before you can damage it; you must use the Osiris to deal damage to it.
After taking out the witch, use demon pulls and angel lifts to reach the key. After grabbing it, you'll be transported to the similar dimension where the giant chained statue is located. Destroy the last chain and watch the next scene. Dante will obtain the Devil Trigger skill afterward. In the next battle, trigger it as instructed and defeat the enemies to return.
After the sequence, jump to the next building where two rages are waiting. There's a gold key in the platform above though it may be a bit tricky. You need to have Enemy Step to give you the necessary boost to reach that upper platform. You have to launch an enemy on the air, pull it quickly using demon pull and use the same enemy as a foothold to launch yourself a bit. Refer to the video to get an idea on how to pull this off.
Take out the two waves of enemies then make your way across Assiel's statue to reach the next building. Upon landing, you'll immediately find a lost soul behind the windows. Turn around and jump to the ledge outside to reach the soul.
Second Lost Soul, Devil Inside
Head inside the next area and take out the waves of enemies. This is a risky place to fight since you can freely fall down so make sure not to stay in the same quadrant for long. After clearing the area, you'll find the gold door immediately as you head out so use the gold key you acquired earlier to open it. (Secret Mission: Gold – Subsistence) After clearing the secret room or getting past it, reach the next area to complete the mission.