Darting sideways as Regulus's first spell cleared the space around them, Lily was quick to level her wand at one newly formed group of undead, seeking to keep as much of the area Regulus' initial attack had gotten them as she could. He would need to be able to focus on the Fiendfyre.

Even if he hadn't reminded her as firmly as he had, Lily wasn't aiming to stun or merely incapacitate this time. What he meant to do required more concentration than she could fathom, or it would go terribly, terribly wrong.

"Bombarda Maxima," she said quickly, hitting one of the undead towards the middle of the nearest group, and sending body parts flying. Repeating the spell Lily sent undead in pieces, hurtling back towards the larger group of attackers, wanting to get them in the line of the Fiendfyre, while hopefully culling as many as she could in the process.

She heard him shout but was too focused on driving the undead as close together as she could to respond. At the first roar of the flames, Lily began to sprint along the side of the blaze as it rushed towards the army of undead, keeping on the side closest to the farm. Keeping her wand raised Lily used the counter-curse to cut a swath of protection between herself and the flames as she moved before, with a loud pop, she apparated, moving towards a spot further ahead where the flames had begun to slip off course.