I read "Through The Moon" before getting to my rewatch of The Dragon Prince...
And imma ramble about it:
Firstly, I didn't know about the comics until I stumbled onto the info.
So if you're like me I'll give a brief summary of what happened:
'Through The Moon' takes place a few months post Arc 1.
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In summary: Rayla is worried they haven't found Virans body, she's also worried about her parents and Runaan. Callum tries to comfort her but it never seems to work.
They go back to the Moon Nexsus and Lujanne offers them more 'Moon wisdom': "White lies are illusions that we make with our words to protect those we love"
She also tells Callum about a ritual that allows you to see the spirits of those lost and against Lujannes warnings they do the ritual so Rayla can see her loved ones and see if Virans dead.
They do the ritual and Rayla almost dies but Callum saves her. She only saw Viran in his magic chrysalis and suspects he's not dead. She insists on going after him and says Callum should stay as she doesn't want him to get hurt. But he insists, so they agree they'll start searching the next morning.
But Rayla sneaks out in the middle of the night on her own.
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Now, for 1, the series confirms that this all happened on Callums birthday!?
Callum had expressed that he didn't want to lose her (and vice-versa) and that they should stick together but she left him for the quest anyway.
Now, don't get me wrong, I can also see this from Raylas pov. She's scared and worried and misses her loved ones and she says that "everyone seems to have just moved on" but she can't shake the feeling something is wring and also wants to learn about her loved ones.
Each time it was brought up with Callum in ended in a small spat/disagreement, Soren was actually the only one to agree with Rayla that Viren could still be alive.
Rayla dis leave a note when she left, but I doubt that didn't help much with how Callum felt. In the series Rayla even says, "I know my leavin' hurt you"
Callum also adds, "Oh so you disappeared for 2 years for nothing!?"
He didn't know if she was even alive!
All this just to basically say,
After rewatching this with new information, Callum deserved to be a bit distant when Rayla came back!!!!