Here's a first look at the new Xal'atath Oblivion affix on the Beta and Voidbound received more changes as well.
Periodically, Xal'atath will spawn 10 Orbs that fire at the mobs. Players can intercept these orbs and gain a stacking buff that grants 2% Mastery and 1% Leech for 20 seconds — one player give the buff to the whole party. If the orb hits the mobs, it instead takes 10% less damage per stack.
As previously announced by Blizzard, Voidbound is getting some QoL improvements but in addition, it looks like the Crit Chance is buffed even more to 30%!