We all know that to get both floors 6 and 7 (Erinyle and Floria, respectively), you have to kill the floor 5 boss, Sa'jeff the Centaurian Chieftain. However, he is really strong. Also, don't forget about those pesky and annoying Centuarian Defenders. Those are what make it hard (and rage a lot!). There are two methods:
"Lure" Method (harder):
Step 1: Get to the boss room. Make sure you have a few buddies too.
Step 2: Lure all the Centaurian Defenders very far out of the room.
Step 3: Kill the boss. Have your buddies lure or kill the extras that spawn. This will take approximately (15 mins. to 1 hour, depending on your gear).
"Kill" Method (easier):
Step 1: Get to the boss room. You will need 3 or more buddies.
Step 2: Have your buddies kill the Centaurian Defenders while you kill the boss.
step 3; blaze it
*TIP: Take regen breaks above the steps as you fight. That makes it a whole lot easier too!
Hope this helps you kill the stubborn boss! When I fought this boss, I used the "Kill" method. I personally prefer and think that method is better. However, it's your choice.