Thanks for tagging me @Karacal! This presents a very possible reality and the results are likely to be very different depending on where it occurred based on the law in that jurisdiction and the views taken by those who are enforcing those laws. I have the relevant parts of the applicable Kentucky statute listed below.
For instance in Kentucky, if something happens in Louisville versus happening in Grayson County, they will be treated very differently.
Based on Kentucky law, the vagrant outside who just broke the window is “presumed to be doing so with the intent to commit an unlawful act involving force or violence.” Under that presumption, I am justified in using defensive force against the assailant. And, based on the person being armed with a deadly weapon, the kitchen knife, and other dangerous instruments, i.e. the hammer, I would be justified in using force, including deadly force, based on the knife which is a deadly weapon.
I think the bigger question becomes should I use deadly force? If I went out and the person runs, let them run. If they advance on me, then yes, force will be used based on that threat.
As in many scenarios, we do not know what might happen. If you do nothing except call the police, the vagrant could escalate things. He busted a bathroom window, do you wait for him to try to climb in or for him to try getting in a door?
Keep in mind that there are many shades of gray and very few things are black and white.
KRS 503.055 Use of defensive force regarding dwelling, residence, or occupied vehicle – Exceptions.
(1) A person is presumed to have held a reasonable fear of imminent peril of death or great bodily harm to himself or herself or another when using defensive force that is intended or likely to cause death or great bodily harm to another if:
(a) The person against whom the defensive force was used was in the process of unlawfully and forcibly entering or had unlawfully and forcibly entered a dwelling, residence, or occupied vehicle, or if that person had removed or was attempting to remove another against that person’s will from the dwelling, residence, or occupied vehicle; and
(b) The person who uses defensive force knew or had reason to believe that an unlawful and forcible entry or unlawful and forcible act was occurring or had occurred.
(4) A person who unlawfully and by force enters or attempts to enter a person’s dwelling, residence, or occupied vehicle is presumed to be doing so with the intent to commit an unlawful act involving force or violence.