People forgetting as usual that the next logical step after MC kills foreign douche is foreign kingdom declaring war, it's a tactic as old as politics.
Step 1: Send notable, at least somewhat disposable knight/noble to lead band of "bandits".
Step 2: Raid and pillage around main roads and villages of [foreign kingdom you want to go to war with].
Step 3: Wait for [foreign kingdom] to kill knight/noble alongside "bandit" group or otherwise imprisoning them.
Step 4: When [foreign kingdom] sends envoy to question why your knight/noble was committing crimes in their nation feign ignorance and be outraged that "[foreign kingdom] dares to besmirch the name and honor of my kingdom!? You falsely imprison/kill my people and slander their name, then dare come here to slander the honorable name of my Royal family!?! THIS MEANS WAR!"
Step 5: Now that the war is the fault of [foreign kingdom] and not you warmongering your people are very onboard with it.
Step 6: Profit.