Arknights: Guide to 3 Star GT-HX-3

Week two of the Grani event has begun!  And with it, arrives a new Big Boss to kill, Big Adam, and we face him head on in GT-HX-3.  If you are looking for guides on GT-HX-3 Challenge Mode or other HX Stages, you can find the guides here:

In this article we present a strategy for bringing down Big Adam in a big way, and reaping the Furniture and and Side Mission rewards. This particular strategy is brought to you by your friendly neighborhood Peacecow.  His video showing this exact plan in action can be found here and via the Youtube link at the bottom of this article.  More Arknights videos can be found on his Youtube Page.

The information should be sufficient to give you a good idea how to emerge victorious, though we will likely be making improvements and adding detail during the week as time allows.

There are two main map components we need to be aware of.

1. Corrosive Ground - Operators deployed on these tiles will have their Defense halved. On this map it only appears on ranged tiles.  This makes the enemy snipers particularly dangerous, as they will quickly take down any ranged unit, even if they are in range of a Medic.
2. Blocks - The player has 10 Blocks that they can place on basic melee tiles.  Each block costs 5 DP and there is a cooldown of 5 seconds between uses.

• 2 Vanguards, V1 and V2.  V1 must be a Skill-DP-Recovery Vanguard.  For V2, a kill-DP-Recovery Vanguard is preferred, but a Skill type will be fine.
• 2 Medics, M1 and M2.  Single Target Medics. Put your stronger one at M1.  Note that in the video and screenshots below, Lancet-2 is used.  Lancet's Talent allows him to not be counted toward the Deploy Limit.  This allows us to deploy an extra flex Operator to the field.  If you aren't using Lancet, then skip the deployment of G1.
• 3 Casters, C1, C2, and C3.  AoE is preferred, but one Single Target Caster is probably ok.  Don’t forget about 12F and Lava!
• 1 Defender.  D1. 3 Block Defender.
• 1 Support. Su1.  Preferably a slow type to stall the boss.  If no Slow support is available, a Single Target Caster might work instead.
• 1 AoE Sniper.  S1.
• 1 melee DPS. V3. Used to kill enemy snipers.  A Kill-DP-Recovery Vanguard like Grani works great, but any decent melee damage Operator should work here.

2 remaining Flex spots per your preference:

• Guard for DPS (G1 below)
• Defender for extra block or emergency death replacement.
• Medic
• Even more AoE casters

Here is an example of a team that can work:
 

The concept is to funnel all the enemies together and beat them down with as much AoE as possible.  Placement should be done as shown in the image below. The following placement order should be done exactly as presented to ensure the proper units get attacked, and each Operator and Box can be placed as soon as there is sufficient DP. B represents a Box to be placed by the player. 

Deployment Order: V1 > B1 > B2 > V2 > M1 > C1 > C2 > S1 > G1 (if using Lancet, otherwise skip) > C3 > replace V2 with D1 > M2 > V3

Once this formation is in place, enjoy the slaughter and wait for Adam to show up.  When he reaches your Defender, use your cooldowns and hold on for as long as you can, but your Melee will die.  Wait for him and any remaining enemies to pass your team and start heading up toward the exit. Then we remove B1 and place it as shown in the image below.  Also place B3.

The boss and any remaining enemies will turn around once their path to the exit is blocked, and will head back along the path shown in red, through our tunnel of death.  Once The boss has completely passed our team, we will do the block swap trick again, removing B1 and placing it in the position shown in the image below.

Again the boss will pass by our team for a beating.  We continue this process until the boss falls, and enjoy our sweet rewards!  Congratulations!