Fable II

This will actually be a bit easier as a good natured person because people are more willing to follow you.

First you will need to gain entry to the Temple of Shadows. It is located in Rookridge near the exit towards Oakfield. At the gate, there should be a guy in a black cloak with a quest; he may not appear until you get the Hero of Strength. His quest is to eat 5 crunchy chicks, which he gives you, in front of him.

Once you do that, go through the gate and down the stairs. Once at the bottom, go through the tunnel. The room you come to has a circle in the middle of the floor; this is where you need to bring people. Go back to town and get as many people who are willing to follow you and drag them back to the temple (it should have been added as a point in the Areas menu under Rookridge). Once they are in the circle, pull the lever at the edge of the circle near the back of the room. This should sacrifice any who are in the circle. There is a small chance they could have walked out of it but they normally don't.

NOTE:
If you have already done the mission to defend the Temple of Light, then you can no longer use the Temple of Darkness as you have killed their leadership.

An easy way to knock this achievement out of the way is by doing it immediately after opening the Wraithmarsh demon door, the one that requires an audience of 10 nobles to see its dramatic performance. Since you've already gathered the nobles, why not get more mileage out of them by leading them to the Temple of Shadows?

Watch the video below:

Thanks to Newfiekeir for the video !

For this one, you need to make 10 people follow you, and take them to the Temple of Shadows, and then sacrifice them. Make sure that you haven't done the mission where you have to defend the Temple of Light. If you've done that, you need to start over, or find someone with this achievement, join their game, and see them only sacrifice ONE, and the achievement should unlock. If it wouldn't (Super rare cases), keep sacrificing another 9, and it'll most likely unlock).

Or you could use the guide below:

I've helped 100+ unique players with achievements in Fable II and I have no intention in stopping. Players join my game, and I will unlock the achievement within a very short period of time after you've joined. The procedure is swift and requires nothing from you except that you have both of the DLCs installed. This can be either the free versions or the premium ones.

As long as this achievement is up, I'm offering the help. Simply send me a friend request, and a message stating the reason you've added me, and I'll help you the next time I'm free. Please don't send me messages asking me when you can get help, as I always keep in mind my "businesses" and I won't forget about you. And because my friends list is set to only have certain people, I can therefore not keep you on my friends list, unless we've agreed that I will.

Now, go ahead and send me those messages! I'm eager to help out :)

Unlock this, and every other Fable II achievement in the Fable II Walkthrough