When you or a friend or your minion does enough damage, the enemy if not already attacking that person/minion will begin to target them.
Does hitting the enemy with a spell that is part of the enemies weakness automatically draw their attention toward you regardless of the amount of damage placed by another player/minion?
I'm not totally sure but I know when I'm playing with my friend and she uses her Dragon spell, all of the enemies focus on her. They absolutely HATE that spell. I can cast a hard hitting tempest spell and they don't switch focus on me like that.
When you or a friend or your minion does enough damage, the enemy if not already attacking that person/minion will begin to target them.
Does hitting the enemy with a spell that is part of the enemies weakness automatically draw their attention toward you regardless of the amount of damage placed by another player/minion?
No, it is dependent upon amount. Any attack (if they haven't been attacked before) will usually draw attention to the attacker. If there have been no attacks, the attention will be focused on order of arrival to the battle (the first two enemies will focus on the first wizard). If several attacks have been made, the highest damage dealer will be targeted. Also, if you are healing yourself or others, that too will draw attention. There have been a few times with my ice wizard I was unable to taunt the enemy from another wizard, because their damage was just too much.