Gideon, Ally of Zendikar

The 0 is the ability that broke the cost curve. A four-mana planeswalker that immediately replaces itself with a 2/2 body has already paid back the tempo most planeswalkers bleed in their first vulnerable turns: the opponent can attack the loyalty, but now there is a Knight in the way, and the planeswalker is still sitting at four. That self-protection is what let this card slot into aggressive white decks without a board built around it, because it functioned as its own blocker the turn it landed. The +1 is the second mode rather than the first: it turns the planeswalker into a 5/5 indestructible attacker on a later turn, with all damage to it prevented, so once the board is established the same card becomes the threat that closes the game. The summoning-sickness restriction matters here, and the design respects it: the +1 is a turn-two play off this card, not a turn-one alpha strike, which is why the 0 exists to fill the gap on the turn it enters. The −4 emblem then converts the tokens the 0 has been making into a clock that does not care if the planeswalker dies afterward. The three modes describe a single arc instead of a menu: make a body, become a body, make every body lethal. The lesson it left behind was structural, a planeswalker that survives early aggression by adding to the board rather than hiding behind it.