Simplify the following text for a Grade 5 native English-speaking person.
Original: Siegfried arrives , disguised as Gunther using the Tarnhelm , and claims BrÃ 1\/4 nnhilde as his wife .
Simplified: Siegfried arrives , disguised as Gunther . BrÃ 1\/4 nnhilde is horrified to see a person she thinks is a stranger .