How does "Loyalty" work?

[Kael]

I dont understand the system. I am trying a vasall-run atm. But even when everything is "worse" on the faction i want to vassalize, they still have something like:
"-200 loyalty"

And when i breakup ANY contract, a different empire vassals them instantly.

Can someone tell me where i can get info about this system? Because i cant see any logic behind it.

[HappySack]

It's pretty simple, without specific civics or ascension perks you will generate increasing amounts of negative loyalty for every vassal you have.

Otherwise there are all sorts of things that can increase or decrease loyalty but to make new vassals you need to have a strong military or they won't take you seriously or think you can protect them.

[PlutonArioch]

As always in this game: read the tooltip, it tells you why their loyalty is so low.
Loyalty builds up or sinks over time. You should try to make their loyalty change positive and then wait. Having multiple vassals gives every one of them an increasingly negative loyalty change("Divided Patronage"), unless you have either the "Feudal Society"/Franchising" civic, or the "Shared Destiny" ascension perk.

If you don't want to learn about it from the game itself, you can also read about it here: https://stellaris.paradoxwikis.com/Subject_empire#Loyalty

[Waffles]

Not being very specific as to whats causing that lack of loyalty. Give em free expansion and politics, limit your holdings to two until you have a number of vassals, and use those slots for loyalty generation. If you have to many and dont have something to counter the loyalty malus for having to many vassals they arent going to be on your side. It also helps somewhat for them to like you, and under no circumstances can they have greater fleet power than your own.

[ScreamCon]

You need fleet power. Lots of it. They will not submit if you don't have much more than them. Like you want x2 to x4 more fleet strength. Active not potential. Entry agreement acceptance is separate from the continual loyalty. You can get them to accept but then you have to recover from a negative loyalty situation. Adjustment of the agreement may be needed to get enough positive loyalty gain.

Also how good the agreement looks will also determine how easy it is to get them to accept. However its not 'only' how good it looks. They will still not accept if your on par militaristically. Empires don't like being vassals unless they perceive the need to be one, or suffer destructive outcome their citizens desperately do not want.

[Sero]

I say your vassalage contracts are very restricitve to the vassal so they don't like you very much.
Just imagine the vassal as a person.
What you are trying to pull off is probably more somehting akin to a protection racket while the other empires that vassalizes the right away is more like an employer or even worse a sugar daddy.

[Kael]

we had very good relations and all these stuff.
But it still got the 190 vassal mali. Even when i had 3x the time his fleet and stuff. they wont accept anything.