The MC is the first prince not the crown prince because he is a beta and beta’s can’t inherit the throne his younger half brother is technically the crown prince right now since he’s an alpha. As for the MC’s mom he was the empress before the MC was born however because the MC was born a beta and beta’s can’t inherit and because the Mom also became infertile after the MC’s birth. Therefore the king brought in Ludmilla and because she gave birth to the second prince who is an alpha she became empress.
Hope this cleared things up! I think this is all a translation error however someone is uploading quality translations so you should just wait for those cause Whalemanga is basically the new Zinchan or Kaiscans.
Oh and the ML is the Grand Prince because he is the current Khan Kingdom Queens brother not the emperor (he can’t be a regular Prince because that would require being his sisters son) again it’s all a translation error.
Is MC the crown prince or not? Is ML a prince or an emperor, is MC's mom the empress or is it ludmilla??? All these mix ups in titles is messing with my brain.