I would suggest not to make a pit in the traditional sense with yagluth, rather dig a double ditch to keep interlopers out and using the dirt from the double ditch to make a wall around the spawn point tall enough to black yagluth's line of sight.
I will explain my logic now: Once you get tired of losing your life, going through your nearby sheltered portal and picking your gear back up while your doing it by yourself..... You will have a change of heart and when you do, you might realize by blocking its line of sight and using an aoe weapon like a giant hammer...... yeah been there. I killed Yag using my big hammer and a soil wall in order to prevent him from attacking.
On the plus side i love Yag's battle music!
Don't forget your nearby portal to jump through when you die!