You can find many passages with her in the legends, where she came to be imagined as a war-goddess in the literacy myths. Going from her name etymology, which was included in landscapes, an Mhór Ríoghain could also be said to be an early designation of the mother Goddess. I recommend reading The Lore Of Ireland by Dáithí Ó hÓgáin to become more familiar with her, and other Goddesses.