This boss isn't really that hard. You can go in with assault rifles and riot gear and beat the boss with 7-10 players. Bring a ton of bullets and healing brews because the defense units do a good amount of damage. Rockets will take out the overseer super quick. Also bring fur gear because it gets cold in some parts. 3 sets of everything are a must in fighting the boss and units. Thank you.

Can be fought after ascending in the alpha tech cave. Bring long range weapons and take out the minions first for they will kick you off your mount.

Bring a gun and hope

If you want to fight it your going to need at least 5-10 people and 4-20 tek T-Rex's. and bring a really good gun.

Bring tek rexes maybe a yutyrannus and a few daeodon, take out minions first with a rexes tek gun then go to hell with overseer. Good Luck!