Gears & Stats
The strength of Destroyer is about it's CC (Crowd Control - Stun/Knockdown/Gorggy etc...) and high natural defense stat which one will want to exploit as much as possible while fighting any shadow of Mushin and to maximize your DPS.
Attack - 451
Hit Rate - 112%
Crit Rate - 37%
Crit Damage - 213%
HP - 34,285
Defense - 29%
I am using a generic weapon with only 194 ATTK to lower my overall attack power to match a level 45 HM 5 stats along with 3 Gems.
Amethyst (Purple Gem) - 3 ATTK and 200 Lifesteal. You want the highest gem possible to maximize your DPS and keeping up with damage received in between HP recovery pots cooldown.
Ruby (Red Gem) - As I am not wearing any outfit and not gaining any benefit from Bopae (Soul Shied) so that I can lower my overall stats, Ruby gem kind of make up for the lack of Crit Rate with the chance to crit on my next two attack while attacking.
Aquamarine - I use this mainly for the chance to recover 10% Chi while taking damage as I lack Chi regen on the generic weapon being used.
1st Shadow - Scar
In this skill build I have point in all CC skills with 3 skill points to spare. No point is required in Grab (F) as Scar cannot be grabbed at all.
The key to beating Scar is to constantly CC him before he Force Choked you and maximize your DPS. In between CC you have 1 to 3 seconds to chain your next CC. If you are quick enough you can CC him during the Force Choke animation or if you have a good a good rotation of your CC skills you can CC him before he even attempt to Force Choke you to be safe. If you have burned all your CC skills you can avoid the Force Choke by either using Flame Wheel (C) or Back Step (SS) 2:00. If he spawn the Ice Circles try to position yourself in between two of them as if he manage to Force Choked you he will throw you in the direction he is facing and you will most likely die if he throws you in one of the Ice Circle.
Your main damaging combo is stunning him with either Earthquake (1) or Ram (2) then Rage (E) for the Crit buff and Pulverized (X). During Rage (E) buff duration you will have 0 defense so you may use Stomp (3) to gain 200% defense and 2x lifesteal.
2nd Shadow - Hatred
In this skill build I have put at least 2 points in Grab (F) (Branch 2 Tier 2) for the 6 seconds duration and max points Slam (Z) (Branch 2 Tier 3) for the Chi recovery. 2 points in TAB Escape (TAB) in case I need escape his stun attack.
Similar to facing Scar, you want to constantly CC Hatred to maximize your DPS. In between downtime of your CC abilities you want to constantly using Cyclone (TAB) to resist any of his stun attack which will result to death from his full combo if you don't manage to escape the stun with TAB Escape (TAB).
To avoid the flame wave, it's fairly simple and fool proof. Every time Mushin jumps back to the center, this is the cue of him about to cast flame waves. Go to any edge of the map and wait for him to cast the flame waves. (I personally use the sound cue to know when he is casting each flame wave but you may face him for visual cues) In between the 2nd and 3rd wave SS back towards Mushin and use Flame Wheel (C) to avoid the last flame wave and either use Flamming Wheel (C), (1) or (2) to close the gap and stun/grab him out of the center.
Note: Every time Hatred backstep from you, you have to CC him straight away of else he will unleash a chain of attack with a final knock-up which will most likely kill you.
Every time you knock him down, he will do a spinning kick recovery attack that will stun and result in him doing his full unavoidable combo on you resulting to your death. If timed properly you can block the attack or just resist the stun with Cyclone (TAB).
3rd Shadow - Darkness
Key Point: After each AoE debuff, you need to CC him straight after or else he will spawn the ice circle and hover while doing Ice Palm attack at you follow up by a knock back. I usually use my (1) or (2) + (E) + (X) combo on him straight after he does AoE debuff as generally those skills are off cooldown and it's a lot of DPS right after you get the additional damage from the debuff.