Assuming you all are talking about the final boss, level 7 should be more than enough. To put things in perspective, I won the fight at level 6 (classic difficulty) although half way through the fight I leveled up to level 7. Prioritize survival rather than going head to head against Alexander or the worm. Let the two elephants pat each other down. Utilize smoke to block sight cones and break aggro and blessed smoke to go mass invisible. And don't be finicky with your items obviously. It's the last fight so go all out. Kill off stray magisters whenever you can and keep the worm in check with CC when it starts to get out of control. The key to the fight is to play the balancing act. You don't want either side to get a significant upper hand. You want them to punch each other silly so you can come in to mop up.
