The Age of Decadence

This guy did a great videoguide on how to get this achievement in under 7 minutes.

It also includes Great Vengeance and Furious Anger achievement.

If you save before interacting with the console, you can also get Godslayer if you deactivate the last working machine.

In the top floor of the Tower of Zamedi, you will find a sphere, by figuring out how to use this, you will unlock the achievement.

To Try figure out how to use it You need a [Intelligence + Lore = 18].

This check open a portal to Monastery Interior Chamber and there is a second check [Intelligence + Lore = 19] to open a portal to The Temple.

You need 4 or maybe all of the following artifacts in your inventory and a high enough lore skill probably 10 lore, (I read you can show the artifacts to Abukar in Maadoran's Observatory in the Market District instead)

These are the things I had while doing my Praetor Run

The Jellyfish Artifact found in Teron (https://ageofdecadence.gamepedia.com/Jellyfish_Artefact)
An astrolabe I bought off the Curio vendor in Maadoran's Market District
Darius Helm from the Quest in Act 2 from Lord Gaelius (You have to prevent his assassination then get the helm then tell him the helm got buried to keep it)
The Ghost Hand found in the Tower in the sky when you go through a portal in the town of Inferiae (https://ageofdecadence.gamepedia.com/Inferiae)
A mysterious Artifact found in Zamedi Tower once you agree to help the demon there and go through the portal, the artifact is in the first floor in a small table.
The moment I picked the mysterious artefact in Zamedi, that unlocked it for me, but there are other artifacts you can get that might count towards this achievement.

You might unlock this with different artifacts but I read Darius Helm is a must, but noone is 100% sure.

Check this list if you still to find more artefacts: https://ageofdecadence.gamepedia.com/Category:Quest_items

You need to switch allegiances twice in a single game, basically betray your House twice.

I did this on my Praetor run, first starting serving House Danaran during Act 1 and getting to Act 2 and the next town, then saving Lord Gaelius from assassination and pledging my allegiance to his House.

Follow the questline until you get to Act 3 and meeting Meru, the lord of the next big town, do as he says and awaken the entity in Al-Akai, when the entity takes over and asks you to Kneel, do so, this will count as betraying Gaelius and this achievement will unlock.

There is another way to do it, which I read in an achievement guide here: Csontzuzo's Achievement Guide for AoD

Here is the relevant part:

Start as merchant or join merchant guild, make sure you have 8 int starter stat, you need to be silver tongued heavy statwise, there will be 1 fight tho, but imperial guards can win the battle your main task just to survive.
Do the raider camp and aurelian outpost quests, well, make raiders attack the post.
After this you should be able to pledge loyalty to house Daratan while speaking with the lord.
Now progress on commercium quests until you visited boatmen. Dont try to make lord avoid the need of proofs.
Tell to commercium you need to collect proofs, but dont forge it by yourself.
Go to the Imperial Guard Barrack and offer your services to Carrinas.
Survive the Battle
Take the documents back to Linos for heavy loyalty loss.
at this point you can save which is recommended as you could make other achievements too like Kingmaker.
now go to daratan compund and dont insult antidas. with persuation and trade skillcheck twice you can offer him to be Emperor.
Now when talking to Carrinas after a persuation and trade skillcheck you can use your 8INT to make Carrinas to promote Antidas to Emperor after 2 INT skillcheck, if one succeded or not going for second you can get diplomat achievemet.
Once passed both INT skillcheck, select the: "This is a very valuable document. Take it and get out of Teron as fast as you can." to get this achievement
reload and choose the Take the document to Antidas instead for the Kingmaker achievement.