"In the non-violent condition, however, participants with higher scores in Machiavellianism had a higher increase in cortisol" - linked study
So people trying to be manipulative bastards in 'nice' games increase thier stress? Interesting.
Unfortunately the source study appears to be paywall and not yet on sci-hub, so don't know what specific games they used. As to how they define Machiavellianism, I assume something toke this:
"In the field of personality psychology, Machiavellianism is a personality trait characterized by interpersonal manipulation, indifference to morality, lack of empathy, and a strategic focus on self-interest." - Wikipedia