User blog comment:Real Godisme/Chapter 481/@comment-25111584-20160411135846/@comment-71.50.117.48-20160411154634

Yeah it is, -__- interference is based on jumping in or take part on an activity or something that's already happening to prevent or carry out on which mostly sometimes don't got nothing to do with them. Like someone getting in a fight and their friend happens to jump in on it to either help them out or stop it, that's interfering which in this case is what Natsu did in that chapter by stopping Jacob from killing Lucy with a knife and take part of the fight (god knows why Mashima never made it different) and he does so most of the time of Lucy fights. And besides dude, if she was never there for her spirit to save them, then there was no way Natsu would ever fought Jacob at all because he would've been gone like the guild members were and of course dead so you can say he's pretty much lost without Lucy too sometimes as she with him and this isn't the only time such as like you said, his fight with Gajeel. And another thing, you currently like Natsu's fights, and more importantly, ERZA'S?! O__O