After completing the quest In Their Footsteps for the Skyrim plugin Undeath, there are three quests that can be done next. These can be done in any order. Once all three have been completed, the quest Scourg Barrow will start.
Arkay the Enemy
"The Necromancer's leader, Antioch, is seeking to use a Tome stolen from the Vigil of Stendarr to become an undead Lich. He has already departed for the Dragontail Mountains in search of something, but has sent some of his followers to destroy a Temple of Arkay in Falkreath hold and take the Heart of one of its Priests. I should hurry there and stop them."
Should you choose the option to release the Priest of Arkay, the quest will update.
"I have freed the surviving Priest of Arkay."
It will now be impossible to complete the path to lichdom yourself. If you choose to release him, let the priest exit the Temple before you do, as this quest won't complete until he has exited, and he may not exit if you leave before him.
"After reaching the Temple of Arkay and defeating the Necromancers I found there, I released the surviving Priest of Arkay and let him escape."
Should you decide to proceed along the path to becoming a Lich yourself, it is necessary to kill the bound Priest instead, and choose that option.
"I have slaughtered the surviving Priest of Arkay. I should now extract his Heart myself."
Once the Priest is dead, take the Priest of Arkay's Heart from his corpse; it will be needed later.
"After reaching the Temple of Arkay and defeating the Necromancers I found there, I killed the surviving Priest of Arkay, and cut out his heart for the Necromancer's ritual. For some reason, I suspect this will come in handy."
"The Necromancer's leader, Antioch, is seeking to use a Tome stolen from the Vigil of Stendarr to become an undead Lich. He has already departed for the Dragontail Mountains in search of something, but has sent one of his followers to Winterhold to locate and dig up the body of a former Archmage from the College of Winterhold. I should find them and prevent them from taking what they are seeking."
Once at the bottom, make your way to the burial site, where there are two Necromancers and Wynestra and the excavated coffin.
"I have found the gravesite of former Archmage Vyngald, which is being desecrated by Antioch's Necromancer followers. I must stop them."
There are enough predators in the area that, by the time you reach them, the Necromancers may have already tangled with them, and quite possibly lost at least some of their number, making defeating them much easier.
"I have discovered and defeated a group of Antioch's Necromancer followers who were desecrating Archmage Vyngald's burial ground, before they were able to obtain the raiment they were seeking. I can re-cover Archmage Vyngald's grave site and allow him to rest in peace, or take the Shroud of Vyngald from the coffin myself..."
Choosing to rebury the coffin means that the path to lichdom cannot be followed. Once made, this choice cannot be undone.
"I have re-covered Archmage Vyngald's grave, allowing him to rest in peace."
"I have taken the Shroud of Vyngald from the former archmage's desecrated grave. His enraged spirit appeared and attacked me, but I have defeated it."
"The Necromancer's leader, Antioch, is seeking to use a Tome stolen from the Vigil of Stendarr to become an undead Lich. He has already departed for the Dragontail Mountains in search of something, but has sent some of his followers to conduct some sort of Alchemical Ritual on a plateau overlooking the Reach. I should investigate this."
"I have defeated the Necromancers at the Ritual Site. Their strange concoction however seems to be prepared and ready for reagents. I can destroy it to ensure the mixture is never completed, or I can try to finish the Elixirs they were trying to create myself..."
On an altar nearby there are, as well as other items, an Apothecary's Satchel, the Conjuration skill book 2920, Hearth Fire, v9 and a Human Heart. Nearby is a chest containing Bloodroot, a Human Heart, Namira's Rot, Nightshade and a Skull.
Activate the Cauldron and you have two options, Destroy Cauldron or Complete the Ritual.
If you choose to destroy the Cauldron, it will be tipped over and the path to lichdom cannot be followed. Once done, this cannot be undone.
If, instead, you choose to complete the ritual, choose that option. There are two different potions that can be made by using the cauldron, Namira's Corrosion and Embalming Essence, but only one of these can be made by the player, and the decision cannot be changed afterwards, so this may be a save point, albeit one that is very early on in the quest series.
The difference between the two potions is in the final appearance of the Lich; Namira's Corrosion results in a skeletal figure, and Embalming Essence in a preserved corpse.
Namira's Corrosion requires Deathbell, Namira's Rot and a Skull; Embalming Essence requires Bloodroot, a Human Heart and Nightshade. All the ingredients needed to make both potions, bar the Deathbell, can be found in the nearby Chest.
This would be a good point to save the game in case of error. Select the correct ingredients for the correct potion from the menu that appears; using the incorrect ingredients results in failure to make a viable potion, and means the quest cannot be completed. Once one potion is chosen, this choice cannot be undone.
"I attempted to complete one of the concoctions that the Necromancers were trying to create at a strange Cauldron I found. I have succeeded, and claimed the Elixir, 'Embalming Essence/Namira's Corrosion'. I should hold onto this until I can discover its use..."
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