After playing with Morgane Merlin's plans, he can finally go back to his time after he has sent Morgane back why he could not go back to Camelot to fulfill his destiny of protecting Arthur

Morgana attacked the Intouch family because of their relationship with Arthur and Merlin. To put it simply Ae is the descendant of Merlin his father has just revealed him after discovering that their ancestor is with his younger son and son-in-law and Pete is the descendant of Arthur he discovered in the general tree of his father's family

So that's why Ae so kindly protects Pete before becoming her boyfriend and her husband because of Merlin and Arthur's friendship and that their son Harry is a wizard

They decided to have a party to say goodbye to Merlin with Alexandra singing for him and Merlin for some magic tricks

After the party and Merlin has sealed Harry's powerful magic by promising Ae and Pete that once he was old enough he would train him after that he went back to hawking through a magical portal that he opened