Kiki by alial778810@gmail.com

/summon Villager ~1 ~ ~ {Profession:2,CustomName:"Kiki",CustomNameVisible:1,Career:1,CareerLevel:42,CanPickUpLoot:0,PersistenceRequired:1,Invulnerable:1,Offers:{Recipes:[{buy:{id:"diamond",Count:4},maxUses:9999999,sell:{id:"emerald",Count:1},rewardExp:false},{buy:{id:"emerald",Count:1},maxUses:9999999,sell:{id:"diamond",Count:4},rewardExp:false}]}}