Sharp Ends (spoilers)

I finally got through the "bonus chapters" in First Law and to Sharp Ends final chapter about Logen in his... younger days.

Now after reading that, my questions are mostly about why do you think Dogman stayed with him all that time? I mean, he was REALLY insane there.

Also, Thunderhead was actually happy to see him back when they reunited, which... doesn't really fit the Logen we saw in these "dueling days" of his, as Bethods champion. I get Black Dow being okay for Logen to get back, because... well I'm sure he was all the time just looking for a time/way to pay Logen back. Threetrees was sadly dead at that point, I would've really wanted to see his reaction to Logen coming back. Grim, I'm sure just went with the flow and was happy to be with the strong men that were there.

So, while I get the rest of them, kind of, if Logen mellowed some between the time we first started in First Law series and Sharp Ends, but Dogman was with him through the worst shit possible. Why did he stay with him? I get loyalty, but Dogman also seemed to be one for... justice. Was it just that he had known Logen for such a long time? Also, we got a lot of Dogmans inner thoughts while they were apart and I didn't see any great hatred towards Logen there. Or remember it.

Also (sorry about the long topic text) do you people think Bethod could've actually made North somewhat of a good place, if it wasn't for Logen? There was some talk about the cruelties he did, but when it comes to Northmen, I'd imagine he thought that was the only way to make his point. Strong points, for strong people. My only problem with this really is, his war with Union. Was there some clearer reason on why he went that path? Or was it just "conquering means more conquering" kind of mindset? He seems surprisingly reasonable in most cases (naturally I'm forgetting his greater faults at this point, so be kind to remind me). I take the "tax collectors" cruelties away from his sins, since... well he had no control on them anymore.

Now, I'm sure this has been answered in this sub, or somewhere in the internet, but Reddit search is what it is and I didn't find anything proper from google. Also, you people were surprisingly alive when I asked my last questions, so I'd be more than honored to get some thoughts this time too.