I played about 300 years of a tiny-ass Indian North Korean count slowly working my way across the landscape.
Playing as a Buddhist is honestly pretty boring though, especially if you don't share a border with the Muslims. There's less stuff and events compared to the other guys and you will basically spend years just waiting for claims. You only get one use of the subjugation CB per character and that costs FIVE HUNDRED karma to use. Unlike the other guys, there's no easy event to get karma other than the single feast you get once per year (even then you only get 30). The subjugation CB also only works on guys that are the same culture group as you.
For the rest, it's all just waiting for the fabricated claim.
The only thing I like about being a Buddhist is that I get to specifically choose my heir.
War elephants are also a little shite. Especially since you're forced to get them with archers as a retinue.
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I got North Korea mode to work simply by not giving a fuck. What I've seen so far is:
1. You get something like 20 troops per province as your tax income is almost nonexistent. You get something like .1 gold per province.
2. All your barons and your courtiers will obviously be -100 relations with you. Only your wife and young children will be unaffected.
3. No one seems to assassinate you or try to do anything to stop you even though everyone hates you. I was under the impression that if your spymaster despised you, you were probably dead. This apparently isn't the case as every single one of my rulers has lived a long and happy life.
4. No rebellions ever.
Since you get almost nothing from your land, you have to subsist on pillaging everyone, retinues, and mercenaries. This is not hard at all when you consider that many barons have over 1000g to donate to you when you banish them.
It's weird though. I was really expecting more assassinations. I haven't seen any effects on my courtiers at all. My council all do their jobs just fine too. The fun part is that I maxed out all the taxes and laws and still no troubles for three centuries. Course... it doesn't do anything as I still only get pennies per province. My provincial capitals also all don't improve either since there's absolutely no point. There's also no one to convert religions and stuff too.
Since everyone perma hates you, you can just freely be a completely evil bastard without any consequences. Every time I conquer a new place I just banish everyone. If I see someone that looks ugly, boom. Banished. That guy is bothering me about prisoners? Banished. Wife being annoying? Executed. Children being whiny? Kill them all and make new ones.
I should just rename myself North Korea honestly.
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Edit:
I forgot that my current ruler happens to be the reincarnated soul of himself. I don't know how that works. Some kind of recursive thing:
Here's a screenshot of the current game: