But i recommend not to do it.

Spoilers after this so don't read it if you don't want to know it.



Because the invasions are getting stonger with each boss.
So if you want to build nice bases without annoing raids (only some pigs) than don't kill him.
I know you get the pickaxe from him but there is another way to go further.

Instead go into the dark forrest and let a troll destroy the ore for you. It's not difficult. I did the same in my currently game and it is so much more relaxing.
Ah one other important thing never kill a Troll. NEVER. (Because it will trigger another Invasion Event)
If you do this you can build really peacefull.