Although technically, Galeforce is under the tree of RB, i would like to discuss about it under its own section. Galeforce damage is extremely high for such as short CD skill (6 sec), especially when you are using the right bracelet and Mystic Badge (to be detailed later).
It can only be triggered after you hit with Repulse (the trigger condition used to deal crit hit with Repulse, until this patch). Take note it is Repulse, NOT Eradicate, which means you can only have a chance to trigger Galeforce every alternate RB hit.
You must unlock the Hongmoon secret technique as Galeforce serves as your ONLY reliable way to recover HP (must be Tier 5) as a Shadow Destroyer. Furthermore, it also serves as the Focus recovery skill to replenish Focus consumed by continuous casting of Eradicate/Repulse. Although Galeforce generates 30 Focus on hit, you will need to deal critical damage to gain the additional 120 Focus over 4 sec. You will need to have pretty high crit rate (60%+) to trigger this often; in fact, you MUST have a high crit rate for Shadow Destroyer build to work because of this skill.
Now that you see how important critical rate is, equip double and/or triple crit red/hybrid gem to further boost your critical rate.
Soul of Pain is strongly recommend (if not a must) for Shadow Destroyer due to the continuous Focus recovery effect, in case you are not getting the critical hits you need. Again, this strengthen the role of Shadow Destroyer as a continuous damage dealer. Soul of Destruction is generally less compatible with Shadow Destroyer (unless you want to use it for Execute (X), to be discussed later)
Advantages of Galeforce VS Mighty Cleave (F)
1. Shorter CD
Galeforce CD – 6 sec; can be reset with Eradicate when using Mystic Badge #2 from Sky Basin.
Might Cleave CD 24 sec; can be recovered by Wrath when using Mystic Badge #1 from Sky Basin; recover 6 sec CD per hit.
The Mystic Badges #2 from Sky Basin is extremely good. It basically reset the CD of Galeforce everytime you hit something with RB. This effectively means Galeforce has 0 CD!
2. Condensed & instant damage
Galeforce damage: 1100%
Mighty Cleave damage: 600%, followed by 2400% over 8 sec
Although the total damage from Mighty Cleave is higher, Galeforce delivers its full damage in 1 hit, while Mighty Cleave leaves the fire on the ground to deal damage over time. Boss often moves around and Mighty Cleave rarely deals its full damage. In most cases, Galeforce deals higher damage.
Galeforce enjoys the same damage bonus from bopae as Eradicate/Cleave (which is 30% for Extreme Furnace). Mighty Cleave is rather special since it enjoys up to 100% damage boost from Extreme Furnace Bopae.
Disadvantages of Galeforce VS Mighty Cleave (F)
1. Unstable Focus regeneration
Mighty Cleave generates 120 Focus over 8 sec when it is cast.
Galeforce gives you 30 Focus on hit; the 120 Focus over 4 sec effect only applies when you deal critical damage with Galeforce.
If your critical rate is low, you will often run of out Focus. However, this Focus regeneration issue can be solved somewhat with a good weapon, Soul of Pain and Willpower buff (to be detailed later).
2. More conflict with Knee (F)
Due to its shorter CD, you will cast Galeforce more often, and tend to have input conflict with Knee since both of them trigger on critical hit. Accidentally apply Daze on boss can be a party-wiping mistake in certain boss battles.
Many players suggest ‘locking’ Knee by going into Stage 2/3. However, this would also mean that you lose the only active mean to apply Daze status.
I believe it is situational. If the boss cannot be cc anyway or it does not matter if it is Dazed accidentally, just leave Knee at Stage 1 (also recover 30 Focus on crit).
Earth Destroyer typically specs into Stage 2 for the damage resist effect. Shadow Destroyer will need the Stage 1 instead.
One of the major changes in July 2016 is that, you no longer need to hit up to 5 times to get the full Willpower buff. A single hit will grant you +100 max Focus (with +20% movement speed bonus) instantly for 15 sec. Having 200 Max Focus is important for Shadow Destroyer.
This allows you to store more Focus generated from semi-random triggering of Galeforce, weapon, Soul of Pain, gem etc. This translates to lesser chance that you will run out of Focus when you spam Eradicate/Repulse.
Although you can no longer reset the CD of Typhoon with Execute (X), you can refresh the duration of Willpower buff with the last hit of Execute. The CD of Typhoon is 30 sec; Willpower buff is 15 sec; if you use Execute near the end of Willpower buff, you will extend the buff by another 15 sec. By the time the Willpower buff expires, you are ready to cast Typhoon again!
If somehow Execute does not land its last hit, it is not the end of the world. You are normally fine with just 100 Focus and Fury can be used to replenish your Focus. Worse case scenario, just cast 2 Judgment to gain some Focus back to restart your Eradicate spam.
Take note that, you will lose the handy damage/status resist effect of Stage 2 Typhoon but you can still resist Knockback with Stage 1.
Also, Stage 1 Typhoon only cost 10 Focus and generate 10 Focus on crit. Although Typhoon can be cast continuously, only the 1st cast applies Willpower buff on hit. If you cast continuously, the buff will not be granted/refreshed even when you hit an enemy.
Stage 1 Typhoon damage 1st cast: 1200%
Stage 1 Typhoon damage subsequent cast: 300%
The damage of 1st stage from Typhoon is actually pretty good (almost as good as Execute x 1), despite the fact that it is not meant to be a DPS skill.