Suggestions for G21 Section

An effective strategy for the Doppelganger is to lure it to the edge to prevent aggroing the doppels, then smack it a ton (at least 30-40 hits) with Brionac until its protection is almost fully decreased, then use a fast attack such as Final Hit, Chain Blade, or Dual Gun and attack until its down to 50%. After 50%, when it gets the shadow stacks, either windmill it so it'll cancel, or get on a mountable pet and let it hit the pet (desummon the pet before it dies, or have an auto-revive pet, or have many mountable pets hotkeyed), and attack as normal otherwise.

I did find [guide] that helped immensely with coming up with this strategy.

My friend was struggling for weeks on this battle due to the lack of information on this wiki, so hopefully this information will help someone.