You gotta be careful with this taru, because it also has Grim halo~ on my attempt it did Grim Halo (400 Dmg or 3 Shadows gone) + Astral Flow (Fernir 2hr) which instantly wiped the entire alliance....
Best to have a bard for Dark Carol and to sleep the Element>> also I suggest 2 Tanks actually tank it while 2 nins stand far away from the party so after it blows its 2hr it doesnt despawn.