From the release announcement: "Rise, Gravelord Azir, rise!"
"He knows neither victory nor defeat. Even the bloodiest battles simply strengthen his army.
Command the dead beneath your black banner with Gravelord Azir, now rising from the League store for 975 RP (until December 4 23:59 PST, 1350 RP after that)."Soldier on for preview images and video!
Gravelord Azir1350 RP / On Sale for 975 RP through December 5th
[Click here to preview Gravelord Azir's voice processing!]
Finally, here's the 1920 x 1080 version of the Gravelord Azir splash art: