Over the arcs in Fairy Tail, we ran into a lot of crap Zeref made. (demons, eclipse gate, R system) and now that we know Natsu’s his little brother. So does that technically count as the little brother breaking the big brother’s stuff? Think about it!:

Zeref:“mom! Natsu killed my demon Lullaby!”

Natsu:“it was attacking me and my friends!”

Mom:“Natsu quit breaking your brother’s inventions, Zeref, quit making things that would hurt your brother or the entire world!”