Skyrim:New Allegiances

Quick Walkthrough
#Go to the specified location.
#Turn the target into a vampire.
#Report back to Vingalmo.

Detailed Walkthrough
When asking what can be done to help around Volkihar Keep, you may be directed to Vingalmo. Speak to him, and he will tell you:
:''"I've found a new candidate, ripe for Harkon's Gift. I'm sending you to welcome this soul into our family."

Depending on who the target is, he will go on to say one of three things:
:"Haran manages the inn in Winterhold. A forsaken place under the shadow of the mages guild. She will help us keep an eye on the mages.
:"Valindor of Riften has his ears in places that we'd love to listening in. Joining our family should increase our possibilities in the south."
:"A pathetic creature in her present condition, but the gift will embolden her. And her lowly state suits her to being our eyes and ears in Markarth."

He then instructs you:
:Put her/his mind to rest, allay her/his fear through vampiric seduction and when she/he is in a pliant condition, embrace her/him and bite her/him on the neck."

Additional questions on various subjects will be available before setting out:
:What do you mean by allaying fear through vampiric seduction?
::"Our blood grants us power to calm and relax. If you currently lack the gift, forgo feeding for a day and that power will come naturally. Once your thrall is suitable sedated, you will be able to impart the gift without resistance."
:Can't anyone become a vampire if bitten by one?
::"While the blessed state of undeath can be 'accidentally' conferred - consider the brutish creatures you find wailing in dank hovels in the wild... Only those who can trace their ancestry through Harkon's mortal   can faithfully accept the power conferred by his Vampiric blood. And among those, it seems, only when the heavens show the correct aspects. I have found such a soul and the stars appear cooperative."
:Why am I able to bestow the gift of Harkon's blood?
::"Because he himself bestowed upon you a portion of his vitality when he infused you with his own blood the night you returned with Serana. A small measure of his blood now and forever flows through your veins."
:Understood.
::"When you offer the embrace, do so away from prying eyes. Our new sibling will then likely require rest while his/her blood undergoes the change. Return to me when your part is done."''

In this quest you are required to infect either Haran, Valindor, or Cairine, earning their allegiance to the Volkihar Vampire Clan. Vingalmo suggests that you use Vampire's Seduction to ease the process, but biting the target while they are asleep will also work.

Valindor
Valindor can be found in Riften and starts off his day by waking up at 4am and having a long breakfast for two hours in his house. At 10pm, he returns to his house to sleep for six hours until 4am, and repeats his schedule the following day.

Cairine
Cairine can be found in Markarth and spends her entire day at the Warrens. She rarely sleeps, and instead sits on the ground, making her an easy target.

Haran
Haran can be found in Winterhold at the inn. At 2am, she sleeps in the inn's cellar along with her daughter, Eirid.

Once you have bitten your target, they will be part of the Clan. Return to Vingalmo to complete the quest.

Notes
A coffin will be added to each new vampire's home, which you can then use to sleep and get the vampire rested bonus. The new vampires do not seem to use it however, and will still sleep in their old beds.
Dialogue conditions in the game data suggest that it could have been possible for Orthjolf to give this quest, but he doesn't.

Bugs
 
Use the console command   to move the quest to the next stage.
One fix to this bug is to kill the already infected vampire. It marks the quest as "failed" but still completes it.
Another fix is to load a previous save from before accepting the quest and try again, as they may not give the same quest.
 Finish any other active quests from the vampires, then go outside the castle and save. If any of the vampires send you to Vingalmo for work, reload the save, and, while outside, enter the   in the console. This will complete the quest and give you the reward, and the questline will progress as usual.
After completing the quests for Vingalmo you can kill all targets and never receive the quest again.
 
Reload from last autosave (should be from when you walk in) and feed from sneak mode.
 
 One solution is to select her via the console (or by typing  ) and enter the command   which should force her to stand temporarily, or   which should move her to you and force her to stand for longer. Once you close the console, immediately use your Vampire Seduction on her and rapidly press the activation/talk button, which should then allow you to access the feed option. Optionally, you may wish to toggle nearby Garvey's detection by selecting him in the console and typing  .
To get Cairine to stand up, you can also punch her with your fists or use a weak spell in order to engage combat with her. Then you can just use Vampire Seduction.
 
 

Quest Stages