Future?

Yup I agree with you there except maybe Soowon martyring would be one of the possible sub plotlines that the author might consider taking.

I do think it is possible that Soo Won is the sword but Zeno side that he “is the dragon made to be your shield.” He said this around the time they realized he was immortal.

I feel like that's more of Zeno's own philosophy as to what his powers are towards the 'king' and his internal strife (an example is that when he told king Hiryuu about his powers, he was disgusted with himself about them) than about him being the shield that protects Yona. By the same degree, Kija's arm is also known as the perfect spear (though I can't remember where that this was said sorry)
Thank you for your input ;)

I feel that rather than taking a shot for Yona, it's more like protecting the country as the shield. It would make more sense as he currently is doing just that. Trying to protect the country and being prosperity to it despite the means of how he did it in the beginning. He still is trying to achieve that as he goes around trying to solve each clans problems but Yona keeps beating him to it. What he did was unforgivable but I do understand why he did it cause if nothing was done, the country will fall into ruin sooner than later. I don't hate him but doesn't mean I didn't dislike him at first. I just came to understand him a bit more. Though I do have a feeling he'll most likely die by the end for Yona and the others.