User blog comment:IamJakuhoRaikoben/Chapter 374: Revolution, Review./@comment-4449950-20140308005225/@comment-7418318-20140308021948

In that case sorry for the misunderstanding.

I think "Lucy thinks" or even "Lucy is sure" would bring your point across better, since "Lucy knows" sounds like it's actual fact, rather than just Lucy's assumption.

Putting semantics aside, I see your point, but on the other hand, just using her whip alone will likely not be enough to support Natsu sufficiently, so sooner or later she will have to use a spirit I think.

I think the best solution would be for Natsu to drop a line like "Careful Lucy, don't let him touch you or he'll suck out your strength, I got only away because Happy bit him in time." and have Lucy figure out that this is how Fran absorbs beings.