Card Rulings talk:Yubel

"Tributing 1 monster or destroying "Yubel" is a Trigger Effect that activates during your End Phase. You make your choice when the effect resolves."

So If Skill Drain is on the field, does Yubel still need to tribute a monster at the end of each turn? Also, if Skill Drain is on the field, when a monster atk Yubel, will Yubel receive damage?