Obviously, Udon's rage at losing Moegi would make him Obito 2.0. He eventually finishes the Moon's Eye Plan, bringing eternal darkness to the shinobi world.
Konohamaru will witness Udon killing Moegi and lose his mind aswell as him casting away his ideals, thus creating another Obito.
I'm not calling it I'm speed-dialing it.
Konohamaru would be forced to kill her, leading Udon to become an avenger and attempt to destroy Konoha. Konohamaru is the hero and only one who can stop Udon.