We have also made a special effort to ensure that decisions producing an advantage can be used both by you and for the benefit of a close ally, which in the context of a multiplayer game allows for increased interactions between participants. For example, a decision that allows destroying a bandit lair can be played in an ally's territory to help them, and the same goes for combating the plague. It goes even further as some personal decisions can be played on one of your armies in an ally's territory, such as recruiting local troops. Send one of your generals to a distant allied region, if you know the troops will be useful, and thus recruit 'exotic' units, such as camel riders or forest runners.
Decisions are used, as we have said, for game rules that cannot be used systematically or by everyone, and thus launching a crusade, a jihad, or excommunicating a nation is managed by the decisions. These decisions are obviously not granted to just anyone, as their consequences are significant. For example, to receive the decision to launch a crusade, you must be among the most pious nations among the Christians, while the Jihad is only granted to the nation that is 'First Muslim'. More modestly, many decisions are more or less rare depending on your nation or the profile of your nation. For instance, the Seljuq Turks will receive a more generous 'Instill Revolt' decision grant than the norm, with an additional bonus each time they declare war on the Byzantine, this being part of their 'Dissent Sower' trait, while the French, through their 'Royal Domain' trait, will receive a decision more often to absorb a friendly vassal. As you see, playing and receiving decisions is rather organic, as it is based on the in-game situation.
When it comes time to play a decision, do not think that there is only one possible outcome and that the probability of success depends on a simple die roll. This may not be readily apparent when you discover the game, but a large number of decisions evaluate their success probability based on the relative skills of the involved sovereigns, as well as other factors, and this can be quite involved in the end. For example, assassinating a sovereign is a decision that you can play on a foreign sovereign, of course, but also against yours (if you find them really too incompetent). In the first case, the skills of each sovereign, the presence of bodyguards, the authority of the sovereign, the possibility of a spy network, and even the relative treasury of the two nations will play a role (in this case, it is assumed that a wealthy nation can more easily bribe less honest guards).
As for the outcome, you will initially only see the tip of the iceberg, but with a bit of practice in the game, you will appreciate the finesse and variation in the results. To take our example of the assassination again, besides the death or survival of the targeted king, there may be revelations about who commissioned the operation, or not. Perhaps a false lead will be given, maybe the king will only be wounded and weakened. And this philosophy has been repeated for many decisions (even if not all are as detailed), thus the mercenaries recruited depend on your nation and the era, and a trial for witchcraft will also depend on the piety of the victim, their wealth, and their influence.
As you see, the system of regional decisions is extremely rich and allows for great variations in the game. Rest assured, however, that in more than a year of testing, our testers have never told us that it overturned the table too much or added too much chaos to the games. But it does add soul to the games, at least, and just enough to diversify the game even more.