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Well, as Akuma_River said, he could have choose another method but... could he ? Remember, at the very beginning, when Yona tells her father that she wants Soo Won and no one else, he answers very seriously that he has always given her anything, that he will do so in the future, but he can't give her Soo Won, it's the only thing she can't have.
I don't know why he said that, why he is so opposed to Soo Won, probably it's linked to the death of Soo Won's father. Maybe, deep down, King Il knew that Soo Won hated him and wanted revenge.... Or maybe he guessed what kind of King Soo Won would have become and he disagreed...
And, Soo Won said once (when they were kids and Hak told him he shouls married Yona, that way they would be together forever) he said (to himself) something like : "When I'll be king, you and Yona won't be by my side".
So he knew he had to kill King Il (as well as Yona and Hak ?) for a loooong time now...
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I completely agree with what you said. I think Yona's dad did know how Soo Won felt & Soo Won killing the King wasn't as a result of a decision made overnight. Of course i'm not saying killing the king was the right course of action because he simply could have dethroned him but then i have a feeling none of the other tribes would have followed him while the old king was alive, hence his drastic action plus of course the revenge he perhaps always wanted.
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He wanted revenge, isn't that simple? The king ll killed soo woon's cherished father, regardless the reason he did it, and he did the same, so what's the problem here? King ll killed woon's father then soon killed king ll "eye for eye and tooth for tooth". We don't know yet the king ll's motives but soo woon's did had a great reson, people were dying, the empire was in ruins, threatened and divided...by the way soo woon is my favorite character!!(≧∀≦)
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I could have guessed he was XD He's not my favorite one, but I love him a lot too.
What's bothring me is that, even if he wanted to get his revenge... He was still a kid when his father was killed, and didn't he get close to King Il ? King Il considered him as his son, didn't he ? ... But now that I'm thinking about it, I don't remember seeing Soo Won and the King together, while Soo Won was a kid... Neither did we see them together while he was an adult... Or I don't remember correctly (but I read the whole story for the 5th time two weeks ago...).
Nah, I agree with you. He wanted revenge, and at some point, he was right to think that he could lead the Kingdom in a better way than King Il. And Shywife86 got a point : by simply dethroned him, he probably wouldn't be able to gathered the strengh of the 5 tribes.
He's a complex character, and that's what make him and interesting one !
Once again I'm beginning to question Soo Won's act. Why did he have to kill the king? Must he? The way they only speak by eyes made me faint but at the same time. Both of them are so cool (though I like Hak better) and it reminded me again by what Soo Won did that suffering Hak and Yona. Stop killing me, sensei! ヽ(`Д´)ノ