Board Thread:Speculation House/@comment-4830106-20140725003808/@comment-24994749-20140802052448

I have two theories about surnames:

1) If Yang and Ruby are native to the Island of Patch (where Signal Academy is located) it is possible Patch and continental Vale have different naming customs. Patch uses matriarchal surnames and continental Vale uses paternal surnames (like the Arc and Schnee families).

2) Kids take the surname of the parent they inherited their semblance from. If the white cloaked figure we see during Volume 1 opening is Summer, she too had the rose petals so Ruby might have inherited her semblance and those her surname.