Rikku ripped open a small garganta in an alleyway somewhere is Moscow, Russia and stepped forth from it looking for something to eat. She hadn't yet recieved further orders and was hungry so here she was. She tried to keep her spiritual energy low as she snuck around the dark skied city and eventually struck pay dirt as she found a group of hobo's huddled around a burning barrel under some railway.
Poor guys were gutted before they managed to realize how much danger they were in. She had purposely looked for weakling because she herself was still not very powerful. Her body had unique and powerful abilities but she was still only at a lower vice-captain level and that was a problem. The faster she devoured lots of souls and got stronger the better because in her world the weak died and the strong survived.
Once she finished her meal she started looking for the next. Making sure to clean the area up of all evidence, or at least she hoped she did, before leaving.