I'm trying to downgrade myself from King to Duke...how do I get rid of the dang King title?
Just change to elective succession and elect someone not of your dynasty.
Sounds like a great time to die and be demoted to duke, TBH. And all those angry vassals are probably more than happy to help assassinate you.
Oh no, they'll still hate your guts (aka blame) if that -100 was because of your actions.
If it was something because of de jure territory you can fix that by transferring the appropriate vassal to that person. Hovering over the opinion modifier will tell you exactly which title/vassal he desires. Or if you want interstrife bordergore you can give them to the wrong vassals, haha.
If you think your troops is whats causing this then delete your retinues, raise your personal levies and disband them at sea, your ships too, and might as well do the same with your vassalsNope they hate me cause I wrongfully imprisoned every single one of them eight times trying to get them to start a faction to make someone else King. Sadly none of them have the desire to start a faction, because I am just so damn strong...