The last Defender

Enchant only a creature you control.

Enchanted Creature has defender, hexproof, loses
indestructible and has "Pay X life: This creature gets +0/+X until end of turn." Its a legendary Avatar in addition to its others types.

It can block any number of creatures and assignes
combat damage equal to its toughness rather then
its power.

When enchanted creature dies you loose the game.