When would the new legendary hero trailer come up?

On another note, I GOT AN OWAIN AFTER 100 ORBS! HE'S +HP -RES WHICH IS NOT BAD AT ALL, IM SO GLAD, I HAD NO HOPE 'CAUSE I WENT TO 4.75% IN OPHELIA'S BANNER (Though now I'll only have 20 orbs for the legendary banner...)

Sorry for the small rant, but when does the legendary hero trailer generally come up?