Lasso of truth

“How did you catch hold of the jet’s wing at those speeds?  How did you hang on?  What are you, Jason Keralis?  Speak.”
Jason gave an angry growl, his muscles flexing, the tendons in his neck drawn taut.  But he was no match for the lasso’s power.
“What’s happening to him?” Theo asked, a frantic edge to his voice.  “What are you doing?”
“He’s fine,” said Diana, though she wasn’t entirely sure that was so.  “The lasso compels the truth.”
Jason grimaced.  “I am a descendent of Helen and Menelaus, just as Alia is.”
Of course he was-- he was Alia’s brother-- but that didn’t account for his abilities.  “Another Warbringer?”
“Something… else.”  He spoke as if the words were being torn from him.  “I carry hero’s blood.  The blood of Menelaus and the Spartan kings before him.  My mother and father helped me keep my strength a secret.”