Mornstar is the name of a powerful wand in Ni No Kuni. It is revealed that this wand was destroyed or misplaced in the present. Oliver must obtain the wand and is transported, fifteen years into the past in order to to do so.
The first version of Mornstar that Oliver receives is not Mornstar at its most powerful. It is still not powerful enough to open the purple chests and must be completed through the location of three orbs distributed by the Wizard King to his most faithful companions. The power of the orbs however drove them all mad, and Oliver must defeat them to gain the orbs to make Mornstar complete.
Mornstar will only reach it's full potential after the three orbs have been located and joined with the wand. Oliver is incapable of completing this fusion on his own and requires the assistance of a powerful sage which he finds in Perdida. Once Mornstar has reached it's full potential, it will open purple chests and perform more powerful magic attacks.
Astra is the sister wand to Mornstar, both possessed by the Wizard King. Both Astra and Mornstar are associated with light magic. Of the two wands, Astra is the more powerful together with its accompanying light magic spell of the same name.