Bridget Crosby and Martha in “Unfinished Business”

Martha, I can help you if you'll let me. Now, where's your son?

Martha

I don't know... He flew. He flew away.

So he's-- He has completely embraced his Kryptonian destiny.

Martha

Do you know what that destiny is?

No, but the symbol burned into your field three months ago? That's the Kryptonian symbol for "Crusade".