Fun combination:Metalhead + Scion,Giving the ability to perform military rush before 2205.

[Nyaruko]

First let's see the 'metalhead' build.Metalhead is an AI personality that gives -1000 relation toward every empires,For players,relations toward AIs are senseless.
Player can become metalhead empires when conditions are met.

And,When being a vassal,Having -1000 poor relation will lower your loyalty at insane speed.You can insult them frequently to get even faster speed.
Look at my date,2200.5.13,traded all my loyalty out.

One year ago.I can trade again.

You can trade every year, with so strong early economy,even a fool can perform a ultra-fast military rush(before 2205) against every AI they see.
Of course,Even your alloys are enough,You may can't communicate before 2205.Please use 30 advanced AI to ensure your booming.

 

[rubert]

That's hilarious. I love to have Metalhead AI empire in my games but I didn't realize the penalty applies even when the player is playing them.

 

[7ED]

The ingenuity of the Stellaris community never ceases to amaze me. You know this will get patched out the very next patch, so enjoy while it lasts.

 

[Cat_Fuzz]

I have previously gotten the impression that the AI personalities' power limits for declaring rivalries are applied to human players as well, but I never bothered studying it and it has been a while since then.

Fun fact - all ancillary effects from AI personality are applied to players as well, and have done for a long time (see your relationships with authoritarians if you have a democratic crusader
personality for example.)

 

[klopkr]

Damn that sounds like a way to make Metal Head AI not get destroyed by everyone too.

 

[Dementor4]

Faaaaaascinating.

I was doing a playthrough a while ago where several AIs were sending me gifts all the time. I wasn't sure why, but I figured out it was because my "AI personality type" was set to something that really hates the other empires in question, but by my actions I had made sure everyone liked me. The response was that these other empires REALLY WANTED me to like them and the gifts were their way to raise my approval rating toward their empire.

This was several versions ago, so no idea if this is the sort of thing that can happen anymore.

 

[Nyaruko]

The ingenuity of the Stellaris community never ceases to amaze me. You know this will get patched out the very next patch, so enjoy while it lasts.

I hope this exploit get patched and the meanwhile give scion some buffs.
Scion is weaker than ImpFief for several grades like B compared to S.If you don't exploit the trade,the benefits you get even lower than a random AI that vassalize you.
3.4 is a feudal age,And you can't vassalize anyone while as scion.And the pros as a scion are not enough to offset the cons that you can't vassalize anyone.