Diego's magical inheritance was something Lynch very much desired, but facing Diego head-on was definitely not something he wanted.
Although he had never fought him directly, based solely on previous observations, Lynch had already determined that guy was really strong.
If he tried to confront him personally, Lynch didn't have much confidence in winning. Even if he did manage to win in the end, the cost would likely be significant, making it far from worthwhile no matter how he calculated it.
If he wanted it but was unwilling to act personally, then he'd have to rely on someone else.
He had previously considered the Tower, but the Tower had explicitly refused. Just as he was unsure what to do, Grant appeared.
This guy was a Great Knight, a presence theoretically capable of challenging Wizard Power. Lynch had witnessed his strength firsthand and felt that if Grant went, there might still be a chance of success.
