Arknights: Guide to OF-EX1 Normal And Challenge Mode

This guide will step through a strategy for clearing OF-EX1 that will work for both the normal and Challenge mode.  

If you are looking for other Event information or Operation clear guides, see the following:

The main thing to be aware of for this map is that the 3 different spawn points primarily eject enemies that share the same type of strengths and weaknesses.  Organizing your forces around these weaknesses can make clearing this map a breeze.

• Top spawn point/lane is primarily enemies that have strong Arts defenses
• Middle spawn point are the ranged Caster enemies.
• Bottom spawn point/lane is primarily enemies that have strong DEF defenses.

So, our strategy is fairly simple: physical attackers on top lane, Arts attackers for bottom lane, and a DPS to camp the Caster spawn point.

• 2 Vanguards, Block-2 Skill-DP-Recovery Vanguards are the safer play, though a strong DP-On-Kill Vanguard (or especially Grani with her S2) can work on the top path.

• 2 Casters, 1 Single Target Caster and 1 AoE Caster is probably best, but 2 ST casters may also work if they are strong enough (or possibly a Supporter in place of the AoE Caster, especially if they have multi-target capabilities like Angelina)

• 1 Snipers.  1 Single Target Sniper is recommended, though any ranged physical DPS may be sufficient if it can be placed quickly enough to support the Vanguard.

• 2 Medics. Any 2 will likely work, ST or AoE.  This is not a particularly damage heavy fight if handled correctly.

• 2 Defenders. Any 2 will likely work, though having Cuora on the bottom lane with her block-4 skill may come in very handy.

• 2 Flex -  Anything will likely work here, though I'd recommend an Arts Guard, or something with Arts Damage, or a blocker and Arts caster, in case there are any leaks on the bottom row.

Here is an example of the team I used:

Unit placement can be seen in the image below, and deployment order should be done exactly as presented.  Each Operator can be placed as soon as there is sufficient DP.

Deployment Order: 

1. Fang - Skill-DP-Recovery Vanguard
2. Haze - ST Caster
3. Kroos - ST Sniper
4. Grani - DP-On-Kill Vanguard
5. Lava - AoE Caster
6. Perfumer - AoE Medic
7. Ansel - ST Medic
8. Melantha - ST Guard

• Vanguard and ST Caster should be placed on the bottom row first to handle the initial rush.
• I placed Kroos before Gani to get some more initial damage on the first enemies, but you may find you need to place the Vanguard before the Sniper due to DP constraints.
• I faced Melantha down so that she could continue dps when a caster gets past for the double spawn.  if your dps here is strong enough, face it up, or if it is a block-2 it can also be faced up.
• if you use 2 ST Medics instead of an AoE, just swap the position of Haze and Perfumer in the image below, and have the ST Medic facing right.

This should be able to hold the line for a while, but as soon as you have the DP to do so, replace the Vanguards with Defenders, like so:

This will likely hold the line until clear. At about kill 44, a big white armored guy will appear at the bottom spawn, and a double-caster at the Caster spawn. Save the cool downs of the bottom row and spawn camper for this point.  If anything leaks, you can catch them with an Arts dps like this:

Enjoy the OP!