An intensive pronoun re-emphasizes a noun or pronoun by taking the place of its antecedent to avoid repeating the same word.
In English intensive pronouns are formed just like reflexive pronouns--by adding -self or -selves to the root pronoun.
Examples: We did it all by ourselves.
The admiral himself inspected the boat.
The only intensive pronouns in modern English are the following:
myself, yourself, himself, herself, itself, ourselves, yourselves, and themselves.
The words hisself and theirselves do not exist.