Since this Keyword is dead, it`s on very few units, and if you give it to somethings it becomes overpowered, and it`s not a healthy keyword in general, Maybe changing it to something else would be better, and give more of it to Monster cards, making it instead of being Untargetable, to be immune to statutes, would be better in my opinion, so you can`t Apply Poisen, bleeding, vitality, shield, etc etc, but it`s targatable and can be killed with damage, and i do believe cards like Gremist or Caretaker need some resistance to poisen effects, so giving them this keyword would make them viable counters to poisen, beside other possible cards that can have this keyword, also, since Monsters don`t have proper purify, giving them more of this might help them, that`s the idea i got about Immunity.