there's the issue with the 'random dude' approach, that with each next generation there's less of this 'royal blood' in the line. if that's a mandatory for dragons to be made, the next up dragons will be of increasingly less power, and so on.
Is that said anywhere? I believed that dragon + royal gives a new dragon and that then the royals mingle with normal humans to produce more royals. Even if blood purity is an issue, it can be resolved in one or two generations of non-royal breeding once we have enough siblings and cousins.
Ultimately the "best"option for the Ravager/MC might as well be Malagar with the Darja Marriage.
I disagree. The queen is meant to rule over the realm while the dragon is busy, and leaving the fate of your kingdom in the hands of an actual child and her amoral uncle is a terrible thing. Darja is stupid, and once the power truly sets in inside Malagar's head, who knows what that ambitious bastard might do. Malagar overall is one of the biggest loosest cannons out there, he knows the words of power, he's impulsive, self-centered, and he isn't as smart as he makes himself appear. The man marched to the dragon's domain with nothing but a spell he never tested that may not work, and even if it did work, had he arrived a week later he would have been stopped, possibly killed, by the wolf tribe or the mercs. This is on par with Adeline's sad attempt at a coup, except he got insanely lucky.
Adeline, for all her faults, is without a doubt the best out of all the current candidates (which says more about the other possible queens than about Adeline herself). She seems to actually know what she's doing and... that's about it really. She's still kinda dumb and knows the words so she's a liability too.
Honestly if I were the dragon I'd kill anyone who even knows of the words' existence and purge every record with fire then marry someone like Mina who knows how to properly run a kingdom. She may not want to, but hey, she didn't want to have sex with the dragon and look at her now! By now she ought to trust more in his judgement.