Start in 867 as the Byzantine Emperor.

Use Temptation Focus and go down seducer until you get mortal adoration and have a heir which is 16.

Gain Tyranny by imprisoning your kids or courtiers, then releasing them until your vassals dislike you overall.

Seduce several people; rank or house doesn't matter. (In my game I had about 3)

After you reach this point change your crown law to limited and revoke a title from any vassal then imminently surrender.

You should inherit all your titles to your one heir, then plot to murder your father.

After your plot to murder your father is about 80% done or a month or two away revoke from a random vassal then surrender in the tyranny war.

You should become your father and your child should still have his plot against you so wait for it to go off.

The event for your lover dying instead, or you will die.

IF YOU DIE, just reload the save until it works out.

There is some information in the comments about further information and tips to succeed at this achievement. seduce un landed women in your court or else they might not save you, and make a custom ruler with seducer and mortal adoration to speed up the process if you want to use custom ruler