Stress System

Earlier games in the franchise gave no incentive for players to role-play as their character. A ruler who was 'kind' and 'forgiving' could torture and execute people while keeping the benefits of their positive personality traits.

I was asked to come up with a system that encouraged players to take these inappropriate actions less often. Because Crusader Kings is a strategy-sandbox game, I did not want to tie players' hands completely; at the same time, I wanted the decision to 'break character' to be meaningful.

My solution was for characters to gain 'stress' when they take actions against their nature. A single transgression here or there can be rationalized away, but as repeated (mis)deeds weigh on their minds, they begin developing unhealthy coping mechanisms or even spiral into insanity. 

"Crusader Kings 3's best feature is that you can get so stressed out you
die, and it's a system other RPGs could benefit from." – PC Gamer

Religion and Faith Systems

In the first Crusader Kings the only religion any player character could have was Christianity. Crusader Kings II expanded this to encompass most of Eurasia and the religions therein, but due to scope limitations the Abrahamic faiths were always the ones that got the most time, attention, and polish.

In order to put all world religions on equal footing in Crusader Kings III, I devised a modular system to construct them from 'building blocks' of tenets and doctrines. Once these blocks were implemented in game, they could slot into any religion where appropriate, allowing us to rapidly create a large number of playable religions representative of their real-world counterparts.

This approach allowed us to ship with over 100 unique belief systems spread across the world, representing not only major religions such as Catholicism and but also minor sects of larger religions and a wide assortment of unorganized pagan faiths – as well as a feature that allows players to craft their own.

"The breadth of cultures and religions represented in CK3 is impressive – it needs
to be in order to match huge world map the game ships with. " - The Sixth Axis

Innovations System

Instead of having a traditional 'technology tree' in Crusader Kings III, we wanted a system which would represent the historical methods through which technological innovations spread across the world. The Innovations system which I researched and implemented the content for was how we did this. Each 'Innovation' represented a specific advancement such as windmills, monetization, and crossbows; once discovered, each innovation would spread throughout the world through proximity, diplomacy, or trade routes.

While the spread of innovations is primarily an automated simulation, we also wanted players to have some degree of agency over their development. We accomplished this through establishing the dominant ruler of each culture as the 'cultural head', who could prioritize the development of certain innovations. While players were not guaranteed to be the cultural head, they frequently were, and when they were not it gave our players something to aspire towards.