Defiance Free to Play

I decided to write my guide out for the 3rd arena "DyDekuso's Chamber", but you should note that if the lag hasn't been fixed yet by Trion, then you're going to have a bad time.

*The method is made to help you get as many kills as possible by spawn killing the mobs and keeping up the multiplier, and boosting points earned by using abilities and bio grenades.*

Before you start:
- You NEED a team of 4, preferably people you know in game and get along with.
- They should have mics, there's going to be a lot of communicating.
- Have a couple of hours the spare, it's going to take awhile to get this achievement.

Your load out should look something like this:
- Protection Spikes and power Stims equipped, protection spikes so you don't go down and power stims so you can have the extra points for a power kill.
- Overcharge power, the instant reload is going to be the most important thing you have*.
- One with electrical resistance is nice but mainly go for... high capacity, low recharge time. There is going to be a lot of enemies so maybe have high capacity over recharge time.
- Any perks that reduce damage to you and recharges your ego ability.
- I find Shotguns and SMGs are best for this solution, shotguns for the mobs and SMG for Dekuso. You should also assign who wants to have a proliferator/bonfire equipped as secondary, they'll have the role of keeping Dekuso on fire or spawning a lot of bugs.
- Bio grenades help too. If you throw one down at their spawn point, they'll land into it and you'll gain some combo points.

*If someone has a zagger with instant reload and infinite ability, he should use blur and kill as many as he can, chances are he'll be your main points earner. I recommend that he is your 'centre guy'.

Now onto the method:
- Firstly, the arena can be spilt into 2 main parts, the time when you can damage Dy'Dekuso and 3 Survive rounds. The survive rounds are timed so you need to kill as many enemies within the round to get as many points as possible. The Dy'Dekuso round isn't timed but rather on how much damage you do to him, he goes into his shield and starts a survive wave when you've done 'X' amount of damage to him.

- The arena has 6 main mob spawn points/areas, not including the 1 in the centre for the Tanker spawn.

- 3 players will stick to the sides, with their backs towards the centre, in between 2 spawn points each. The spawn points are at each of the doors on the walls (the ones that have the graphical glitch making them appear orange) and below them. The enemies will jump down from there and land in the 2 spots that you'll need to keep your eyes on, always.
- 1 player will stay in the centre and watch out for the tanker spawn, and help the other 3 players if any get swarmed or downed. He will also be required the keep everyone in line and warn them when Dekuso is moving around. He should be warning others to keep to the plan and reminding them when to move on Dekuso and leaving 2 enemies alive at the end of the 3rd survive wave.
- The 3 players mainly spawn killing will need to kill the mobs asap; using a shotgun helps a lot since you can kill them instantly, which stops you from being swarmed.
- Kill all the enemies during the survive waves before damaging Dekuso, exception being the 3rd Survive wave where you NEED to keep 2 enemies alive to have a 3x multiplier when you kill Dekuso. I recommend 2 Rioters since they need to be close to attack and they shoot slowly since they need to reload between shots.
- The designated centre guy should be the only one damaging Dekuso after the 3rd survive wave. He needs to get Dekuso's HP as low as possible without killing him, and when he thinks he's done it, he will tell everyone to kill the remaining 2 enemies and then attack Dekuso.

Quick Runthrough
- Start - Run into your designated spots and start shooting Dekuso. Move around to avoid his attacks.
- First Survive Wave - Be in your spots and kill all the enemies. Make sure to kill all before attacking Dekuso. Hopefully there will be a tanker during the round, when/if he shows kill him with a x3 multiplier.
- Dekuso Round 2 - Same as usual, attack until he goes into his bubble and starts the 2nd survive wave.
- Second Survive Wave - Same as First Wave.
- Dekuso Round 3 - Same as 1st and 2nd round.
- Third and final Survive wave - Same as before but keep 2 Rioters alive. I suggest each of the 3 spawn killers leave 1 and the centre guy kill 1 of them.
- Final Dekuso Round - Designated guy should widdle Dekuso's health until he is nearly dead, whilst the other 3 distract the 2 remaining mobs. When Dekuso is ready, Leader will announce the death of the rioters and everyone should then immediately attack Dekuso.
- Reward Screen - Drink to forget previous failed attempts. Celebrate win.

Notes:
- I found that the lag can clear after about 10-15 consecutive games without leaving, I think it clears as less people are in the server and doing arenas.

**Please comment before giving any negative feedback. I'll change and update the solution as needed. Credit always given.**

I wanted to move this to the top, because this solution belongs more to these guys than it does to me:
CREDIT: Thanks to Pyro1099, Mobius Evalon, and LifeExpectancy for much of the information included in this solution.

This achievement is unlocked by achieving a Gold rating on the nine new arenas in the Gunslinger DLC. You gain access to the various arenas by completing the missions in the three storylines included in the DLC, three arenas for each of the three storylines. After completing each arena with at least a Bronze rating, you will be able to access the arenas from various other locations on the map. You will find three arena access points at each of the following locations after completing them:

- Shondu's Consulate
- Overpass
- Iron Demon Ranch

Due to the new scoring system, it is essential to work as a team in order to achieve high scores in the arenas (as well as Incursions, Arkfalls, Arkbreaks, Seiges, and other raid-type activities). Sorry, all you guys who like to play solo (like me), but Trion just bent you over. Anyway, teams of at least three, and preferably four, are pretty much essential to achieving good scores in the arena events. There are no time limits for arenas, so adjust your strategy accordingly. Some other helpful tips:

- Only one person in the group needs to achieve the gold medal score. As long as at least one person has a score qualifying for a gold medal, everyone in the group will get gold, as well. There seems to be an exception to this if one or more players are "down" when the match ends. It seems that there is either a point deduction for getting downed, or else you finish the match with the score you had when you got downed.
- Open experimental weapon chests, gather gulanite crystals, etc to rack up extra points.
- The experimental weapons are pretty worthless, so avoid them other than opening the chests.
- Don't leave your teammates down. Reviving them gives you extra points.
- You receive a 2,000 point bonus at the end of the match.
- The max multiplier is x3. Time your kills to keep your multiplier up.
- Trigger objectives such as destroying crates, freeing hostages, etc one at a time to maximize the number of enemies you can spawn.

NOTE: Thanks to LifeExpectancy for the following information: There are only 2 arenas that are hard to get gold in, arenas 2 and 3. #3 is the notorious Dekuso one which is impossible AFAIK on 360 due to all the glitches and disappearing enemies. #2 is possible via a farming trick on the tanker. It only took us 3 tries to gold it. All the other arenas we got gold our first attempt.

The required arenas are as follows with points needed for Bronze/Silver/Gold rankings:

- 101 Keys Dock - 15,000/50,000/100,000
This arena will require 4 people to get gold. Split up and kill all the clusters of red dots on the map as quickly as possible. Try to coordinate having a x3 multiplier for the Tanker minibosses.

- Ridgecrest Mines - 10,000/35,000/80,000
You should attempt his arena in a full group of four people. Note that the EMC troopers at the beginning do not count toward your multiplier for either increasing or maintaining it. This necessitates that some of the group need to sprint past and start killing raiders while 1 or two people take out the EMC troops. (This appears to have been fixed by a patch). Farm the tankers for extra points, but even with this, you are probably going to have to use the spam-healing method to reach the score for Gold, similar to the one used for DyDekuso's Chamber.

- DyDekuso's Chamber - 6,500/45,000/100,000
While this one is technically possible to gold with 4 players in a legit manner, it depends on having a deal of good luck since the map is riddled with disappearing enemies and other glitches. Your best bet at this time is to use the "healing farming" exploit. Basically, you leave the last two enemies alive and whittle Dekuso down to a samll amount of health. When you've done this, have three people keep damaging themselves while the fourth person uses a BMG to heal them for points. See the strtegy from LifeExpectancy in the comments below for more details.

- Observatory - 20,000/35,000/50,000
Possible to gold with as little as 2 people, but more is always better. Lots and lots of Dark Matter enemies here. Not much of a strategy is really needed for this one. Just keep killing as fast as you can. Keep an eye on the transporter spawn points. Many times you can get 10 or more kills in a row by camping a teleporter spawn.

- Dark Matter Bunker - 35,000/75,000/100,000
This one is also possible to gold with two people, but as always, more is better. Like Observatory, this map is loaded with Dark Matter enemies. Their pretty lame and easy to kill, but note that enemies will often spawn behind you so it's often best for one player to hang back a bit behind the other. Teleporter Spawn camping is also productive on this map.

- Arkfall Wreckage - 15,000/30,000/65,000
Another level jam-packed with slightly retarded Dark Matter enemies. Gold can be obtained with only 2 people, but again, more is better. Make sure and explore all the rooms before triggering the boss battle in the last room to get as many kills as possible. This map has an occasional glitch where a lot of the enemies don't show up. The solution seems to be to go ahead and complete the arena, and then select "Try Again" from the ending screen.

- Kent Docks - 20,000/28,000/35,000
For this map you need to have a full group of four people and you shouldn't have much problem after that. No strategy really needed. Just split up and kill as quickly as you can. Try to have a x3 multiplier when you get to the two minibosses (Biomen) at the end of the level.

- Berk Academy - 24,000/30,000/36,000
Possible to gold with as little as 2 people, but much easier with 3 or 4 players. Explosives, explosives, explosives! Get yourself a high damage detonator, and equip perks that boost explosive damage, like Deadly Cascade which increases damage by 30% per enemy caught in the blast radius.

- Matron's Nest - 30,000/55,000/100,000
Possible to gold with as little as 2 people, but the more, the merrier. This one is pretty simple. Just keep killing skitterlings, and the the occasional warrior or archer when you have a x3 multiplier. When one person gets to at least 98,000 points, go ahead and finish off the matron.

NOTE: Due to the new scoring system implemented with this DLC, and due to the ridiculously high scores needed for a gold rating, it is currently not possible (or at least highly improbable) to get a Gold rating on some of the arenas. I will update this solution when (if) Trion patches these problems. Good luck! See LifeExpectancy note added to the solution above, or in the comments.

If you're okay with spending a little money or waiting for events, this achievement is much easier now with boosts. They are only temporary (2 hours for the purchasable boosts) but none of the arenas are that long.

You can now get Score boosts which straight up increase your score in arenas, among other places. To start, if you buy a Patron Pass subscription, you will get 50% extra bonus score. From there, you can also buy Self +15%, Self +25%, Group +5% and Clan +7% boosts. The last two aren't really worth it.

So for a few bucks you can easily get 50%, 15% and 25% boosts - 90% extra score, nearly double. This makes all the arena gold scores much easier and very possible solo. Just focus on keeping your multiplier up at all times and only killing bosses/large enemies with a 3x multiplier.

At the time of writing this solution (February 2018) there is also a month long event where you get a free 7 day patron pass and another 100% score boost. So with just the patron pass and event boost that's 150% score, for free! Using this event or potentially future events makes this achievement extremely easy to solo.

You're free to try without the boosts if you don't want to spend or wait for events but this is definitely an option if you don't want to find groups or deal with the tight score requirements on some arenas.