Use device-level protections: PIN or biometric lock, updated OS, and trusted WiFi
Thats worse than the GOAT, but a bad Mayhem Devil still seems pretty impactful, especially with an ability that could turn infinite mana into infinite sacrifices into infinite damage to one target
Arbor Elf has seen a fair amount of competitive play, often alongside Utopia Sprawl
While shes not an early-game character (requiring five Ink to bring onto the field), her six Strength and four Willpower more than make up for it
(It can't be blocked, targeted, dealt damage, enchanted, or equipped by anything controlled by those players.) Fateful hour If you have 5 or less life, you can't lose life this turn, you can't lose the game this turn, and your opponents can't win the game this turn