Justin's magic could penetrate almost any defense from the front, but Nathan's arrows were easily blocked. However, in the air, Nathan could target weak spots, bypassing defenses entirely. Even so, Nathan would attract much less attention than Justin, given Justin's overwhelming firepower.
"If I fly around, it's better for the enemy to aim for me, even if I get hit by arrows. But if I'm in the front and they only target Nathan, it's practically begging for death."
The enemies would be forced to choose between enduring constant magical attacks while trying to counter Justin or taking out the archer first and suffering a fatal blow from Justin's magic. Either way, they'd be faced with an impossible dilemma, and the accumulated damage would only grow worse over time.
"That's why it's better for you to take this. Practice your mounted archery while you're at it," Justin said.