Possible Clues:

• Most senior of two
• Not all feel destiny, like the one most likely to succeed?
• First in the field (estimated)
• Comes first to the Spanish Teds surprisingly
• Inscribed in Gospel: destroying the first-born
• Sibling who usually baby-sits other siblings
• First among progeny
• Most old
• First to arrive
• Characters in novel destined to be most senior