If you choose to kill the character and that character is saved, it will not be knelt.
The reaction of Battle of the Camps happens before the reaction of Battle of the Trident. You can first kneel (or kill) a character with Battle of the Camps, then reveal a new plot after claim is applied. The other way around will not work though. If you reveal this plot with Battle of the Trident, it will be too late to trigger its reaction in the same challenge.