Fun fact about limit breaks, if you're using a paladin tank:
When the slashers spawn, you can have your mage/summoner nuke every single add on the field. Have your tank watch very very carefully for Grudge. Hallowed Ground. Pointmock at boss, finish him off.
If you're using a warrior tank though, tough luck, you're gonna have to bind/kite those adds around.
(This is all for undergeared people though; people with Relic+1 etc etc can just burn the boss.)
