Originally posted by Lithariel:

The very best thing to do first... plaster the area with Campfires. Use a Workbench as a guide where to put them. Most player build items in Valheim "paint" a "Player Base" area around them, 15 meter.
The problem is, that they all count as a target for monsters... the only two not counting as targets are the Campfire and the Bonfire. They both have a 15 meter Player Base they paint around them which prevents monster spawn.

Campfires and Bonfires have a 20-meter range, not 15, so far as I can tell.

Originally posted by Lithariel:

For those Tar Pits... Surround them with Campfires... or drain them. Either fill them up, or dig a hole next to them, open the trench to the tar Pit and the tar runs out. That prevents those nasty Tar Slimes from annoying you.

That doesn't stop Growths from respawning. Only Player Base structures can stop that.

Originally posted by Lithariel:

For melee the best weapon is the Frostner. Since he takes nearly no damage from Pierce(high resistance) and reduced from Blunt and Slash... the Frostner with its massive Frost damage deals good damage.
If you want to shoot him, get Ice Arrows. You won't do a ton Pierce... but Frost as said is good. He used to be vulnerable against those Silver Arrows... not anymore it seems.

Yagluth does have very high Pierce resistance, but he has absolutely no resistances to either Blunt or Slash. As for Spirit, he does take Spirit damage but he doesn't take extra damage from Spirit attacks. Also, Spirit arrows only do 20 Spirit damage while Frost Arrows do 52 damage, making them a better choice.

As for the "best" weapon against Yagluth, it's the Silver Sword, without question. The only particular issue with that sword is it's insane cost to make and upgrade, requiring 160 Silver to reach Level 4. That being said, Frostner itself also requires 120 Silver and also requires Ymir Flesh to make, which might be an issue if the Merchant proves to be elusive.