The memoriam crystal z12 is found on Freneskae. It is one of twelve Memoriam crystals needed to unlock the Helm of Zaros cosmetic override.
Upon my return to Gielinor, I searched for Mah's elder sisters, hoping to convince them to aid in my transcendence. Instead I discovered a horrifying truth about this world. I know now what its true purpose is. It is not for mortals. It is not for me. And only the powerful have a hope of surviving. My path is clear. Though I cannot create life, I can forge it into stronger forms. Perhaps one such form will be our deliverance. My empire has taught me that pushing mortals meets with resistance, so I must learn to pull them instead: to lead them from the shadows. I must become the guiding voice within their heads - their drive, their urgency, their passion and their betterment. I shall become the mortals' will to power. There is little time, and this will take all my efforts. I shall return one last time to inform the cardinals - Azzanadra and Zamorak shall inherit all.