Hope the rabbit is the sort of incredibly strong (or just very strong to put up against some Sabertooth member) and quite funny character (well a serious and normal person in BP would be strange).
Even Lahar and Yajima were caught in his illusion. And Mavis? She should be able to see through that, being a spirit and so.
Maybe they teamed-up the 5 of them to intimidate Laxus (although Iwan/Ivan thought he wouldn't be intimidated the possibility still existed) or just like Qilin said to get things done faster and safer even if his father is at Gildarts's level.
What did Makarov do wrong to have such a kid?
