Temporary Agents (abbr. TA) are the unicorn of the institutions, as they are very rare (they make up around 2% of the institution staff) and only a few people had the privilege of meeting one. They have the same salaries and benefits of an administrator but can enjoy them only for a short time (3-4 years).
They are often chosen for some particular skill that is needed by the institutions, though, as you can imagine, this is not always true.