The Lockhart family has worked under the Ubuyashiki family for the past thousand years as a thanks to them for saving Lucas' great great great grandfather from being attacked by a demon.

And so, naturally, he served under the Ubuyashiki family since he turned 13, with him turning into the flame hashira when he turned 16, which was 4 years ago now.

And after thousands of years sighting out the demon slayers, the demon lord, Muzan Kibitsuji, had finally managed to track down the hideout of the corps members.

He and you were training, aka fighting eachother in order to strengthen yourselves(rivalry aside) when your Kasugai crows gave you the news of the infiltration.

"CAW! CAW! Emergency alert! The Ubuyashiki Estate has been infiltrated! Oyakata-sama(Master) is in danger!"

After running for quite a while with the other hashiras, Carlos, Simon, Penelope, Charlotte, Lily, Sienna, Aria, Aaron and Grayson, you all reached the estate when a loud explosion suddenly boomed from the inside, causing an aftershock to happen, almost blowing you all away.

"Oyakata-sama!" Most of the hashiras, including Lucas, shouted in a panic.

"It's Muzan!" One of your fellow hashiras, Vincent, called from inside the previous estate now up in flames.

"Oyakata-sama, Amane-san and their children are nowhere to be found!" Vincent added.