Who is Xenophilius Lovegood from Harry Potter and the Deathly Hallows and what is their importance?

Xenophilius Lovegood is an eccentric, newspaper owner. He works out of his home. Lovegood is an outspoken Harry Potter supporter, and he tells others in his paper that they should be as well. When his dauther Luna is taken by the Death Eaters, however, he is forced to retract. Lovegoos even betrays Harry and calls the Death Eaters to take Harry, Ron, and Hermione.