it is achieved on weekends naruto chakra, or aoneko can appear .. also in events .. and in the previous update completing misisoens give you frags but very few times

Hello!

If I remembering correctly, Aoneko was given out as a free ninja reward from one of the events in Hot Topics. As of now, the only way to get his/her fragment is through Chase Missions and/or few selected events. Thank you.