First, I am all for playing it how you and the DM want. the DM seems to be setting up a more 'morally ambiguous' setting than standard. Cool. Some DM's allow Paladins of various alignments. Cool. But then I really can't comment. I can only comment as if it was being played in a fairly standard world for paladin morality. So, here goes...
FreeTheSlaves said:
Well murderous thoughts is a bit misleading as it was an execution without the benefit of the prisoner already subdued.
You stated you had murderous thoughts. Then invaded his home and murdered him. Pretty straightforward. There is a difference to trying to 'bring someone in' and trying to track him down and kill him. Paladin is usually very different than 'vigilanti'
King appointed by default as the hierarchy of legitimate law has defaulted to me.
Huh?? So, from what I can tell, the king did *not* appoint you. But you have decided that you are the only 'legitimate' law, and will thus become judge, jury, and executioner, and who needs those pesky trials anyway.
There will be a representative but we don't know how far the Mayor's reach is, so far it seems more than local.
So now we discover that there *is* other law, that may even be 'legitimate' yet it is *inconvenient* for you to try and find out. "Sure,the judge may be a good guy, but we don't know, so lets kill everyone instead" Not how I think of most paladins.
We don't get XP for battles in this campaign and the injuries linger, also we lose as often as we win so the assumption that we'll win any given battle will eventually result in bleached bones.
Well heck, if combat is hard that changes everything. I think your paladin should start using poisen, and killing people while they sleep. And don't forget to torture the prisoners to get better information. The point is, paladins are supposed to be Lawful Good. (with capitals) Not have a sliding scale based on convenience and ease. You should probably be playing a chaotic Good fighter, or Cleric maybe.
The decision to execute him was made during the journey back to town, after I mulled through the legal and moral issues.
One man, out side of the law, with limited information. Judge, Jury, Executioner. I like The Punisher, but he is not usually considered a Paladin.
I'm just saying that it wasn't a spur of the moment decision but very deliberate.
So it was pre-meditated murder. Agreed.
We couldn't burn his house initially because of the indiscriminate killing but as he was escaping I roused the house (only 1 of his sons was home) by calling "fire!"
So, setting fire was too dangerous, until it looked like he might escape. Then it became very convenient. You already said you didn't know who, or how many were in the building. Elderly servants, young children, sound sleepers, people trapped behind flame, people getting injured during the panick, animals injured from panic or flame, etc. etc. These were all people you were willing to put at risk, because you came in to murder someone, and thought he *might* be getting away. It was much easier and more convenient for you to start a fire and risk (maybe) many lives, rather than take a chance he might get away, and you will have to hunt him down again.
Out of the desperation of being boxed in by the flames did the Mayor jump to safety but my deputies scrambled swiftly to intercept.
And murdered him, just as you had intended and decreed. (apparently) no attempt to parlay, no attempt to arrest him. Any grapple attempts? disarm? etc? The guy had no armor, and likely little/no magic. So heck, that just makes him easier to murder.
Well the Carlos brothers were all hired bounty hunters that we had to fight in self defence.
No issues here. You were attacked by bad guys. Fight them, and if they die, it was defense, no problem.
Legally speaking, after he was subdued, there was no reason to detain,
Huh? You are okay with attacking a murdering the Mayor while he was sleeping. But there is 'no legal reason' to detain a hired assasin? Huh?
Now, there is another issue. These guys may have been 'innocent' and not known that the Mayor was dirty. But from your description, I doubt it. It seems the entire populous knew. And since you were (presumable) trying to clean up the town, these guys are guilty of being used as assasins by a very bad man. (Mayor) So, take them to jail. Lock them up. Or try them and execute them. Now, if he was from 'out of town' and didn't know anybetter....then you don't punish him for being duped.
and so we took most of their food to fill our rumbling bellies.
So your justification is that it made it easier on you...
If he was a bad guy, then you are obligated to take him in. If he was a good guy that got duped, you are obligated to help him if you can. Maybe he could help you against the Mayor.
. I would have done last rites but they mean more from someone who cares more, so the surviving son was more suitable.
You are a Paladin. You are supposed to care. Plus, aren't these guys just law abiding citizens that got tricked into attacking you?
The people are largely cowed into submission and don't want to be publicly seen helping us due to the trouble that'll come their way.
You (or your DM) need to watch more westerns.

It happens all the time. Oh yeah, you should also have a pretty high level Fighter in the area, but he is washed up and drunk, and only becomes useful near the end.
my low ranking character being sent.
So, who sent you? If it is the King, let that be known. Put up signs, tell locals, etc. Take back the town. Make new laws, etc. Declare the sons/goons outlaws. Etc. If you are not sent, there should be help not too far away, search them out for validation. And if out numbered, trick them, trap them, arrest the in their sleep. But don't just go in to kill them. Anyway... IMO.