Tony Stark and Thanos are great examples of two different kinds of choleric.
Stark is choleric-sanguine, which means his primary temperament is choleric and his secondary is sanguine.
The choleric aspect is clear in his self-confidence, pride and arrogance, and his air of being the smartest guy in the room (even if he is). He has an indefatigable belief that he can fix anything through his own genius and will.
The sanguine aspect comes through in his vanity, his love of acclaim (though he takes it lightly), his “playboy” love of nice things, and even the aesthetic value of his Ironman tech.
Choleric-sanguine translates into either an INTJ or ENTJ. The top two functions are introverted intuition (Ni) and extroverted thinking (Te).
Stark’s Ni is expressed through his technology, which he creates and wields with the same intuitive, creative flair. Contrast this with Hank Pym and his inventions, which are depicted as difficult to control, rough around the edges, and Pym himself as testy and very particular.
While Stark’s Ni and technology are flawless and constantly evolving, his Te is prone to create problems – as shown in Age of Ultron and Civil War. If Stark stuck to developing his ever-advancing technology half the plot points of Avengers would never arise. It’s his judgement (Te) that backfires in spectacular ways.
For this reason I would argue Stark is INTJ, Ni his dominant and Te his auxiliary.
Thanos is choleric-phlegmatic.
Like Stark, Thanos has an unrelenting self-belief and inner certitude. He is ambitious, though his ambitions are channeled into his own personal crusade to “save” the universe. He is convinced of his own importance as saviour of all life, yet approaches his goal in completely pragmatic and ruthlessly direct ways.
But Thanos isn’t interested in nice things or having fun. His secondary temperament is not sanguine but phlegmatic. His vision of retirement is an austere farmer’s hut. And far from Stark’s impassioned efforts to protect Earth, Thanos slowly and steadily moves his chess pieces into position.
Choleric-phlegmatic is either ENTP or INTP. For NTPs the two main functions are extroverted intuition (Ne) and introverted thinking (Ti).
Thanos’ Ne is demonstrated in his eclectic collection of “children” who serve him in a “this kid might be useful one day” way.
It’s also evident in the very unconventional idea of randomly killing half a population to save it.
It’s also evident in his acuity: how quickly he seizes on a single word or reaction from an enemy and infers the bigger picture.
His Ti is evident in his pursuit of his ambition through what is revealed to be a long-term plan of obtaining the Infinity Stones over the course of about a decade.
Thanos is an excellent example of an NTP using external resources as their strength, relying on their own Ti and Ne to wage a strategic war and a tactical battle.
It’s not always easy to pick the difference between introverted and extroverted versions of the same type. It’s ultimately a question of which of the two main functions appears stronger.
In this case I would argue that Thanos is ENTP, because of the comparative weakness of his Ti and his singular focus on his ambition of saving the universe from itself.
Both Stark and Thanos show poor judgement in their use of auxiliary thinking functions. Stark’s weaker Te leads him to make rash decisions without considering possible consequences or alternatives. He’s so used to being the smartest guy in the room, but doesn’t realise his Ni can be blinkered.
Thanos’ weaker Ti keeps him fixated on his deeply skewed “solution” despite all the self-evident flaws. He is so adamant that his way is the right way, and that the universe ought to thank him if only it could share his vision.
At one point Thanos tells Stark that they are both cursed by knowledge. But Stark’s knowledge was an intuitive vision of an alien threat, whereas Thanos’ knowledge was the subjective theorising of his own Ti.
Ni vs Ne
In their strengths the differences between these two cholerics is instructive.
While Thanos is a great warrior, his true strength comes from the powerful warriors, weapons, and Infinity Stones he has collected and made use of. Even the Infinity Gauntlet he wields is something he himself couldn’t create, but had to use the skills of others to obtain. It’s Thanos’ Ne that allows him to identify and exploit these external powers.
By contrast Stark is the kind of choleric who would do everything himself if he could (and sometimes does, using empty suits as extensions of himself). His power comes from his own Ni, which gives him an intuitive knowing that amounts to genius.
In real life choleric-phlegmatics will have skills of their own and choleric-sanguines will draw on the aid of others, but extreme characters like Stark and Thanos help us understand the core of these temperaments and how they are likely to behave.