Vampire: The Masquerade — Sins of the Sires: Avenger Achievement

The path I have tested and confirmed to pop the achievement is fairly easy. Choose Thinblood as clan. You’ll want to be spending time with Alex, as expected. Once Alex is threatened, go to them. When Nepo shows up, Alex is killed, then of course, promise to avenge them. Then you will be blood-bound and when you get to the fight with the Prince, choose an option that is easy to fail. You will get the achievement if Nepo dies at the hands of the Prince or if they both die.
Skill Check Values under a spoiler tag:
– I use my knowledge: Learned must be above 50% AND Persuasion must be above 40%
– I fight: Intimidation must be above 40% AND Fight must be above 50%, OR if you have Potence above 1 dot, the fight check is irrelevant, but Intimidation is still required
– Stay calm: Composure must be above 50% OR Fortitude above 1 dot
– Sneak up on Peisistratos: Awareness must be above 40% AND Stealth above 50% OR if you have Obfuscate above 1 dot, the stealth check is irrelevant, but Awareness is still required
These values are for what is needed to pass, so if you’re aiming to fail the check, make sure your values are below these.

There are two other points in the code where the Avenger achievement can trigger, though I have not tried them and it is hard for me to read how they actually trigger. These seem to be options where you support the prince in the conflict or the prince survives your failed skill check, though I’m not sure. I’ll go through at some point to find the exact details later.

If you need a precise path that is guaranteed to work, here are the choices that are the most important. The character build is fight focused so the last skill check is easy to fail. Apart from these choices, I always chose the top option that is automatically chosen when turning to the next page.

Consider this your spoiler warning, everything beyond this point is pure spoiler content.

The bolded lines are the choices to make, the italics are the descriptions that come right before these choices. If the choice isn’t described here, it’s fastest to simply click next without changing the default option, as every other choice is, as far as I can tell, irrelevant. Some that are relevant and top option are in here as well.

Remember who you were before you became … this?
– I was the muscle at a club.
You even had hobbies. They seemed important. Everything did.
– I used to hunt animals in the forest.
Unfortunately for you, and perhaps for him, too, keeping an eye on that first door is within the duties of a guy that paces the back of the station, guarding the bits that are not well-lit enough for the subpar CCTV system.
– Knock him out and take his key card.
How do you know which way to go?
– Buildings are made with a sense of purpose, an internal logic. I intuit my way through.
These are the gifts of the Blood to you.
– My skin hardens. It becomes almost indestructible, like marble.
– I am fast. Preternaturally, inhumanly fast.
– I am stronger than any human being should be.
– I have heightened senses.
He extends his arm holding the bag towards you. “A sip?” he asks.
– I prefer my food live and kicking.

She nods towards a middle-aged man sitting alone in a corner. He’s thin but looks healthy enough, and he has a look of profound sadness on his face. Persa has such a feel for always spotting the weakest in a herd.
– Sure, I’ll share.

It takes a moment for your eyes to adjust, but then you see it: the dark unmistakable shape, a body huddled over another body. A pale neck flashing faintly in the light of the monitors. The sound of blood leaving a body and entering another.
– Join them.
Not quite a breach, then. Not yet. But how long before he witnesses a feeding or some Blood alchemy ♥♥♥♥ and something clicks in his head? He means well, and that makes him vulnerable.
– I should stay out of this. It’s not my concern–not right now, anyway.
You have a few more hours until dawn.
– Go to the forest where I used to hunt with Alex.
Alex can’t know about you. For their sake as much as yours.
– Leave them a message. Something cryptic.
– “I’m still here.”

“You shouldn’t be hunting in this area,” he says. “Not when there are so many of us around at the same time.”
– “Say you? Or the Prince?” I ask, defiant.
“So now you owe me.”
– I’d rather support him than owe him.

You no longer have a home, but you must find somewhere to sleep, some kind of refuge. Dawn will break soon; you can feel its pink fingers pawing at the back of your head, cloyingly sweet.
– The forest. Alex will take me in.
You’re going to be destroyed here.
– My only thoughts are of Alex.

No important choices in Chapter 6.

Sophia raises an eyebrow. “Is that your answer, then?”
– Lie to them and then flee and protect Alex.
This scene is where you should meet Nepo and start the Avenge path. All conversations with Alex should lead to their death.
Neoptolemos licks blood from his lips.
– Say nothing. One night, I will avenge Alex.

“And now it is,” Neoptolemos replies. Then, he turns to you. “Help me,” he says.
– Help him.
Of course you’ll help him. He didn’t specify how, though. What are you supposed to do? The Prince was right; what could a thin-blood ever do to harm him?
– I use my knowledge and try to sound convincing.

And with that, Nepo dies and you have avenged Alex. Bonus achievement is Sophia becoming Prince.

If there are any issues with the guide, let me know, and I’ll fix it.