Stupid easily manipulated by his mother, he accuse his brother Will to make him puppet (while he himself was the puppet of his bit** mother just to remove all the obstacles & remain in power), didn't even try to confirm to Will if he was really admiring or respecting his brother, he should go talk to him directly!
I hope she dies miserably if she died, and if not Duke will punish her for false accusations defaming a royal family member! They're so cruel to remove Will's eyes even if he's innocent! Not only contented to kicking him in the criminal village with no way going back since he doesn't even have any magic to return anywhere near them! I hope the 2 other conspirators' clan will be downgraded and not to be trusted much by Duke in the future for making false accusations toward his uncle Will after hearing his story! It's unfair to just let them getaway with everything, specially against a royal blood!
And now he's being blinded by the saintess' legend, not being rational in decisions regarding her since his entire favor evolving around her, not caring enough if Alicia was harmed from the kidnapping and more harm to be done if she continues the role to be the watcher. I hope his reigns cut short and Duke claims the throne sooner, to remove the stupid royal line from throne who didn't even manage to gather info from neighboring countries as his topmost priority since he doesn't even know when war will breakout any moment when there's no information coming in from outside and just focuses on the legend that they're not entirely sure if it's real that she'll manage to save the country. (assuming that whatever happens to the kingdom, war or famine or calamities, saintess will be saving them)
Will's proposals will bring great benefit for the growth of the country but he didn't listen, even Alicia mentions the same sentiment but they didn't take action (so far from the manga, there's no such mentioning of taking action upon whatever Alicia suggested). And just continue the corrupted system with wealth concentrated on just few nobles (even if he himself is having a very hard time managing territories since he doesn't give liberty to make decisions and everything have to to through him or just appoint non-magic users instead for efficiency if there's only bunch of useless magic users not fit for their roles) ヽ(`Д´)ノ