Frodo Baggins

The last clause is the tell. Making yourself the Ring-bearer normally just hands one attacker a pile of upside; here it converts that upside into a targeting problem for the opponent. A 1/3 that must be blocked while it is your Ring-bearer forces the enemy to spend a creature on it every combat, and once the Ring has tempted its way up to attack-time looting and combat-damage life loss, those forced blocks are underwriting a body the defender cannot afford to let through. That is a deliberately narrow lever, but it points somewhere specific: combat happens on your terms, with the opponent's creatures spoken for. The real build-around lives in the temptation trigger, which keys on Frodo's name or any other legendary creature you control entering. A board of cheap legends turns each cast into another advance up the Ring's escalating rewards, and green-white rarely gets to stack a scaling engine on two-mana legends this cleanly. Density is the whole prerequisite, though: a 1/3 that must be blocked only becomes a threat after the Ring has tempted enough to make it one, so keeping legends flowing is what keeps the ratchet turning. Read against the rest of the Ring-bearer legends, this is the one that reaches back and pulls the "must be blocked" static ability into the same loop the Ring is building.