Her aim was to weaken the Will of the realm by killing all of the living things in it. Then she will use bombs to destroy the physical structure of the realm and poke holes in it. This will further weaken the Will of the realm. It will weaken it enough for her to take the fight directly to it.
This is something that all of them have to do. Monarch High Heaven refused to help them anymore, so they have to take the realm heart on their own. Unlike other immortals, she is not afraid of doing this. It is because her speciality is consciousness, mind, and soul.
That means she can fight the Will of the realm directly. She just has to weaken it enough so that she won't be defeated instantly. And she has to do so fast enough before the immortals and world gods of the realm tree interfere.
