How I killed Galiant:
Gunslinger:
2 spots on ability bar of lvl 1 Shatter Bolt
1 spot of lvl 1 Iron Skin
2 spots of lvl 1 Magic Bolt
3 spots of lvl 5 Void
all extra points in regen and speed with breaker gear.
Cast Iron Skin
Void him x 3
Magic Bolt him to death or until Void cooldown is up.
Repeat.
I use Shatter Bolt situationally so it's up to you to know when to cast it.
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