Five first starts developing this Legacy in anger when he realises that Emma had told people about what she had seen of his power, and they were nervous around him. He punches a wall, holds a metal post and touches a shop window and takes on all their properties. In panic he flies to Ethans house and lands on the beach, taking on the properties of sand, his body collapses and he panics. He manages to solidify again, this time taking on the gold on Ethan's watch. Ethan gives him a form of tranquiliser to help him relax.
Five carries around two balls with him; One rubber ball which allows him to stretch his limbs and become flexible like rubber; and one steel ball bearing, given to him by Ethan. He uses this to become as hard as steel. He uses both in the Everglades when he reveals his betrayal. He punches Six in the head in his steel form and uses his rubber form to hold Nine under water. In New York in his brawl with Nine, he turns into steel to avoid Nine shoving a pole through him. However the pole does go through and Five is left with it through him.
Has all Legacies.
- Externa may be related to the word "Extend," which refers to the Legacy extending to mimic the properties of the object it comes into contact with.