Simplify the following text for a Grade 7 native English-speaking person.
Original: Zuko accepts Azula 's challenge of an Agni Kai , or `` fire duel '' , because he feels that something is wrong with Azula and he does not want Katara injured .
Simplified: Zuko accepts Azula 's challenge of an Agni Kai , because he feels that something is wrong with Azula and he does not want Katara injured .