Offtank Garuda Ex (Warrior Help)

[Traek]

In the case you can't hit garuda safely when she starts casting Minstral Shriek, use Heavy Swing right when she lands again, before sisters spawn then skull sunder on chirada, butcher's block chirada, provoke spiny, tomahawk spiny and overpower will secure it.

^ This.

Also, I wouldn't do what Valky said. Instead, while you are in bubble you should Heavy Swing > Maim. This will give you Maim benefit for when Garuda comes back down. Then do as Lemon suggested. Heavy swing Garuda before sisters come > Skull Sunder Chirada > Butchers Chirada > Provoke Spiny > Tomahawk Spiny. Threat will be very secure. Spiny sometimes likes to do a jog to the MT with this method, but don't worry it'll come back. You can Tomahawk x2 if you feel the need, the MT shouldn't be AoEing though, so won't keep threat over x1 Tomahawk.