You need to earn enough multiplayer experience to reach level 30 (131, 771 exp) and complete waves 1 to 30 on the Allfathers Garden map. Obtaining these two goals doesn't have to be in any order, for example you can be level fifteen and complete wave's 1-30. Once you reach level 30 the achievement should unlock.
Once you get to wave seven you should start to find a place to hold up. This map has very little cover so I have only found two places worthy of camping. You can get shot at from several directions so make sure you stay in cover.
The first location would be by the large ammo box; on the right and left side are sniper rifle's, maybe ten seconds from the hold up point. Set up shields next to the barricade, this will prevent maulers from running in. Also try to set up a shield behind the barricade, by doing this the blood mounts cannot jump over. You will have problems with grinders and boomers with this spot; most of them will go either attack from the left or the right but some enemies will move in the center and fire. This location is best for 2 to 3 people, there is not a lot of room but each person can cover either flank or the front. You may want to be inclined to pick up all of the exotic power weapons but you will run through ammo with them quickly at the higher levels.
Probably best to have someone with a Torc or Boom for the flamers, another player should have a sniper, and then the final player can use either. No matter what I would recommend that all players use a Lancer. You get an ammo refill after every round which is very helpful when you start to get to the 17-20 and 26-30 waves. If you can get the boltox that would be great for when those maulers get stopped by a shield, conserve your ammo.
The second location is by the Torc/Boom shot spawn. I prefer this because you have several weapons very close to the hold point: Small ammo boxes, Scorcher, Pistol, Nades and either Torc/B-Shot. Set up your shields so that they will cover an area between the large barricade/flower box whatever whatever it is it cannot be jumped by bloodmounts. My ghetto drawing below will hopefully help you out.
This location is best for 4+ players, you will need many people to cover the perimeter: two for the front and then one on each side in the back area. Back here you can snipe somewhat safely.
The key in this location is to get ammo for your weapons when you have around 5 enemies left. If your a sniper run out and get the sniper rifle spawn or nades etc. Only use the small ammo craters which are outisde of the defense position if you are desperate on ammo. I.E. still a ton of guys on the map and you lancer is empty. Everyone is far apart so that if someone is hit by a boomshot the entire team will not go down.
Choose your weapons smartly; if your sniping in the back you do not need a scorcher. You can use a sniper effectively in the front ranks but it is better for guys in the back. Try not to run out and pull a rambo because you will most likely die, stay back with your team and hold your stronghold.
If you need assistance with this achievement I am more than happy to help you out. Please don't just send me a random invite, be courteous. I may be busy at the moment but I'll throw you on my friends list and we can work something out.If you send me a game invite without a msg introducing yourself or saying that you need help with the achievement I'll just ignore you.
Also if you have any questions or comments or need help interpret my drawing send me a message on live or on TA.
Enjoy my ghetto drawing of the second defending point!!!
I hope that this updated version of my drawing helps out, the periods are just holding a value so that everything will stay in place...
Scorch = Scorcher
'.' = a holding value so that the msg won't delete unused space
|, _ and -- are values to designate walls
basically the scorch is in front of you and you put the shields up so that they are in front of the path. This way bloodmounts can't jump over the shield because they cannot land anywhere. The large 'flower pot' area is in "cannot jump" area.
__ ...........................__ This is the path on the map
..|.......| Jump |.......|
.....|....Boom / Torc..|