Sword Art Online: Hollow Fragment
So, yeah, I'm currently in Abandoned Weapons Lab (or, as Hollow Map says it, "Deserted Weapon Testing Field). There are 4 very tempting chests there that says they're sealed by a powerful monster, but I can't find them.
In Abandoned Weapons Lab there's a room that I can't access, guarded by 2 doors, one says it's sealed by powerful monster, another says the lock has "3 parts", I managed to defeat the monsters in Hidden Arsenal (or, as the Item page says, "Hidden Armory") and obtain Silver, Gold, and Jewel Keys but I still can't unlock that door. I assume that the monster I'm looking for is behind that locked door.
There's a level 142 NM in Hidden Arsenal, I thought that's the powerful monster referred by the chests, but nope not that one. The Hollow Mission in Abandoned Weapons Lab has an NM: Titan, but defeating it does not unlock the chests either. I have mapped the entire Abandoned Weapons Lab except that one room behind the locked door.
31 Answer
I finally figured it out.
The Key
On the map there are 3 rooms filled with Valley monsters: Valley Slash (slime), Valley Stab (knight) and Valley Strike (golem). These are the 3 parts referred to by the door. You need to clear all of those rooms out to unlock the door, in which 3 NM Valley Kings will greet you, basically the boss versions of those Valley monsters. These 3 are the powerful monsters locking those chests, and they all need to die. They're level 126, but the problem is not their level: it's the mechanics
King of The Valley
You may have noticed that the kings have peculiar names: Slash, Stab and Strike. These are actually hints: each is vulnerable to the corresponding attack type, and will NOT take damage (the damage will be 0) from any other attack type EXCEPT EXT Onslaught (the stun attack, defaults to square, deals hopelessly small damage) and Ultimate Joint Attack.
- Slash is vulnerable to Slash attack type (just about all swords and axes)
- Stab is vulnerable to Thrust attack type (rapier, spear and dagger)
- Strike is vulnerable to Blunt attack type (clubs)
Note that status effects that your Sword Skill may cause such as Depth Impact's Defense Down will still trigger.
Most likely at this point you have a plethora of Sword Skill with Slash attack type so King Valley Slash is not a problem; you can bring Asuna or Philia to work with King Valley Knight, let them chip away at the boss as you tank it. You may also tank King Valley Strike while Lisbeth bashes it in.
However, if you do not have access to either Thrust or Blunt, defeating the problematic King is not impossible. No, you can't run back to town to switch people: monsters respawn when you leave the area
Regicide
Recall that the Kings are vulnerable to Ultimate Joint Attack. This is a special bonus attack automatically cast at random whenever you perform a Joint Sword Skill attack.
Note that I said random, I haven't figured out how exactly Ultimate Joint Attack is cast, sometimes it casts other bonus attack (such as Lv.2 Holy Ray or whatever), the bonus attack is announced on the top banner, occupying the same area as other messages such as Praise SP bonus. Only Ultimate Joint Attack will cause damage, any other bonus attack will not cause a dent. In battle, you'll have to try to survive only to wait until your partner asks you to perform sword skill together.
It is advised that you do not try to goad your partner into using Sword Skill by asking her to do so via Call Palette:
- While it is true that you can perform joint attack without having her call out to you, you'll need to time it perfectly with your partner's cast time, and it's much harder than it sounds.
- Asking her to use Sword Skill can and will interrupt her "Use Sword Skill Together" dialogue balloon, which will cancel it, causing you to have to wait again
- Trying to synchronize with the AI (instead of the other way around) is a risky gamble which will deplete your SP when you actually need it. Better save it up for healing Battle Skills or when your partner calls for joint attack.
My Personal Tips
- A partner with good Sword Skill affinity (whichever type is fine) will help a LOT, since she will cast Sword Skills more frequently and call out for joint attack more often
- I recommend bringing Asuna or Philia so you can kill King Valley Stab faster. I brought Asuna and cannot deal any damage to King Valley Strike. The strategy I wrote above is the very strategy I employed to defeat it. King valley Strike does not hit particularly hard. My Kirito was at level 112 with 267 DEF and 164 VIT and the King's attacks do not pose any real danger, the moveset is identical with NM Titan in the map or NM Holy Rock in Hidden Arsenal.
- Use status inducing skills such as Depth Impact (Defense Down) and Shine Circular (Darkness a.k.a Blind), even if you can't deal any damage you still can inflict status, which will help your survivability
