As someone new to the universe (I jumped into this universe this year and I read everything I humanly can from the Black Library), I found strange that a lot of people who comments on the reveal that Titus is fearless since a child just stop there and don't connect with what has been said at the beginning of the episode.
The Imperium control its army with a faith built on fear. Because Titus is fearless, it implies that he has no faith for the Imperium (at least not one imposed to him by the Imperium). Based on the fact he spent centuries being torture by the inquisition we can assume he is loyal to the Imperium.
But there are 2 differences between Loyalty and Faith:
- the fact that a Loyal soldier can't be control
- Loyalty is toward a nation (the Imperium) while Faith is toward a religious figure (here the Emperor of Mankind).
That's why everyone around Titus is afraid of him joigning the chaos. But from what we know Titus is too loyal to betray the Imperium (and is resistance to the chaos may makes him immune to god corruption). But doesn't it put him on a lot of historical figure who betrays there leader when they think they betray the nation? Roman and medieval histories has a lot of those historical figure. Brutus killing Cesar is the most known of all.
Of course Titus will never try to kill the Emperor of Manking but right now the real leader of the Imperium is Titus own primarch: Guilliman who serves as the Regent. Titus is not strong enough to kill a primarch but an assassination attempt would be a big deal on its own (a second Horus Heresy but this time without god corruption).
All this emphasis during all this years on how Titus is unique among the Spaces Marines, to the point where the first mainstream movie/tv show is just about that, I just can't imagine they will do nothing about it.
I am probably wrong, I'm too new to the universe, to really judge my own analysis. That's why I'm writing it here hoping to learn a lot more about that specific subject of the lore (the lore is so big now, it's hard to know what to read to analyze the probability of a theory).