Jak'Sho, The Protean 226665since 13.14.1 6 changes
3000g (3000g base, 2100g sell)
Voidborn Resilience: For each second in champion combat gain a stack granting Armor and Magic Resist, up to 8 stacks max. At max stacks become empowered, instantly draining enemies around you for magic damage, healing yourself, and increasing your bonus resist until end of combat.Mythic Passive: Grants all other Legendary items Armor and Magic Resist.
Builds into: 
The Unspoken Parasite
HealthSpellBlockArmorMagicResist
Click any two patches to compare; the current range is shaded.
− During combat with champions become empowered, increasing your bonus Armor and Magic Resist until end of combat.
+ After 5 seconds of champion combat, increase your bonus Armor and Magic Resist by 30% until end of combat.
− After 5 seconds of champion combat, increase your bonus Armor and Magic Resist by 30% until end of combat.
+ After 5 seconds of champion combat, increase your bonus Armor and Magic Resist by 40% until end of combat.