Any time a creature has more than one Role controlled by the same player attached to it, the creature keeps the newest Role and all the others controlled by that player are put into the graveyard (and then cease to exist as they're tokens)
Unfortunately, Cavalier's low toughness makes it a bit of a liability as even the cheapest removal spells like Shock can easily remove it
during the late 70s as a refugee from Cambodia after escaping the Khmer Rouge
Why wait until turn 5 when you can play Starscape Cleric, then Sorin, Imperious Bloodlord, and use the -3 ability to plop down Bloodthirsty Conqueror
Then they can go out, grab some booster packs, and build that deck with real cards
Having deathtouch and lifelink makes Yarok formidable in battle, but the real prize is its ability to copy "enter the battlefield" effects