Xiao XiRan's proclamation to marry Marlene made everyone dumbfounded. Except from Mo Yao Wang; whose face instantly turned black as a pot.
Mo Yao Wang looked at Xiao XiRan with indifferent gaze; trying to stop himself to strangle his playful grandson. After all, he brought a big destruction due to his selfishness.
It's not that Mo Yao Wang doesn't want Marlene to be Xiao XiRan's wife, but she was previously a witch queen; who made a lot of sacrifices to prevent his grandson from getting killed.
Moreover, even though Marlene is no longer the queen, it cannot hide the fact that she has a royal blood; a lower ranking creature which is only allowed to marry a human.
Since Xiao XiRan has a blood of a Xuè mó; the highest ranking creature in demon realm, the witches are considered as their slave a thousand years ago.