Bethany Hawke as The Morning Star.

• Carver’s proficiency with a sword is pretty much all self-taught. While Malcolm tried to show him a few things, mostly he would come up with his own drills from watching mercenaries spar, then copying their moves with wooden sticks.
• He received some proper training when joining the infantry, but “bitched to no end while doing it.”
• When asked why he joined the infantry for the King’s Army, Carver said he just wanted to protect his family, because “someone had to” after Malcolm died.
• In the Battle of Ostagar, Carver cut his own wedge in the darkspawn horde. Even when it was clear the battle was lost, he refused to give up.
• His fellow surviving soldiers had to tackle him to the ground in order to make him stop, and three men had to drag him to cover, Carver crying the whole time. (Seriously, I can’t stress this enough, if there’s one thing this entry makes clear, it’s that this boy was traumatized.)
• Avris Tanner, his fellow soldier, describes Carver as having “a stare like a templar, drive like a Warden, and more skill than sense.”

• Bethany spent most of her childhood alone in the house, instead of playing with the other children in Lothering.
• One time when she was outside, playing by the river with her and her brother’s friend Ebrin “Peaches” Janith, they were chased by a wild dog. The dog bit Bethany, and she made it go to sleep with magic. Even though Peaches kept her secret, Bethany stayed in the house even more after the incident.
• Peaches brought her books to read, when coming to visit her brother. Bethany spent a lot of time reading and fantasizing about courtly life, with knights and princes. She was caught dancing with a book before.
• Bethany always wanted to be “normal,” and you could tell this even in the way she reluctantly practiced her magic. 
• There was a mysterious figure only identified as Sade, giving the account of this entry. He watched Bethany for most of her life under different guises on behalf of some unknown organization of apostates. Sade made sure Malcolm had everything he needed to train Bethany outside of the Circle. (I’m guessing Sade was a member of the Mages’ Collective.)
• Sade theorized that Bethany would be “Aequitarian by choice… but would have surprised herself with leanings to the Libertarian.”

I kind of noticed this because in the beginning of the game, Carver - even though he has more rivalry than Bethany - seems generally calmer, only really getting agitated when Bethany looks at him and asks ‘why didn’t we run sooner?’ as though he has the answer.

He’s also very calm after Bethany’s death, defusing the situation easily by diverting his mother’s anger and therefore her attention away from his older sibling. Even throughout the rest of the prologue, he’s pretty chill - he only raises his voice when pleading with the guards for entry to Kirkwall, and he makes it a point to tell Aveline it’s his older sibling that is the reason they survived, downplaying himself. He doesn’t even sound bitter; he states it as a matter-of-fact thing.

It might be that, regardless of attitudes toward the older sibling, Carver in general was a more mellow, if still kind of sullen person. If he was at the ‘so stressed im calm’ point it could’ve been a defense for his family - in WoT Vol. II i think, it’s stated Bethany was reclusive and spent more time inside than out, mostly due to worries about her magic. Carver seems like the kind of person to put more into relationships than he expects to get out and was already expected to protect her and Hawke (if a mage), and would’ve likely tried to remain calmer to mellow her out.

Bethany, on the other hand, seems touchy and agitated. She doesn’t like being in the open, she doesn’t like being exposed, and there’s nothing wrong with that. Being out makes you vulnerable.

I haven’t played a full game with Bethany since 2011, so I can’t recall how Bethany’s attitude changes all that much - other than she’s generally agreeable - but Carver seems to be projecting, with Hawke. Maybe before in Lothering he didn’t take his responsibilities as protector for Hawke all that seriously; Hawke’s clearly older and likely did more protecting of Carver, and that’s just how that worked out. But without Bethany there, Carver’s trying to fill the gap with Hawke and he doesn’t understand why Hawke won’t let him.

It doesn’t seem to be a matter of dominance. It seems to be a matter of Carver realizing Hawke has none of the self control or reservations that Bethany had. Not that Hawke can afford to have those things, but for Carver it’s not normal, it’s frightening, and no one’s ever told him he can stop looking out for the family, that he’s allowed to take care of himself.

So maybe it’s projection. Bethany wants to be how Carver was - and what she remembers was the calm and collected brother who stood between her and the Templars. And Carver, he’s projecting Beth onto Hawke, trying to do better all the while expecting better of Hawke themselves (the conversation about Bethany’s death seems to imply that Carver’s disappointment from Hawke came because he had an idealized version of Hawke in his head and now he’s seeing Hawke’s not the strong immortal older sibling and rather than adjusting around that and simply viewing them as a regular authority figure, he’s viewing them as someone who needs to be defended. Poor kid.)

• just kidding haha could you imagine