The Assault Force「強襲部隊, Kyōshū Butai」 are a division of the allied forces of Stigma, the Holy Knights and the Seven Deadly Sins formed during the new Holy War, designed to launch a direct attack on the Demon Clan's headquarters in Camelot.
Before the imminent Holy War against the demons, Merlin took care to divide the allied forces to face them. The "Assault Force" was designated to be the group formed by the minimum number of people possible, in order to successfully infiltrate in Camelot and launch a direct attack, besides of avoid being affected by Zeldris' Piety Commandment. The group was originally formed by Merlin, Escanor and Ludociel, but Hendrickson and Gilthunder decides to join to protect Ludociel and Margaret respectively.
When arriving at Camelot, the Assault Force discovers the castle covered by an enormous sphere of darkness, product of Meliodas absorbing the Commandments.
Ludociel invokes his Sanctuary, creating an Ark barrier around him, Merlin, Escanor, Hendrickson and Gilthunder, being able to enter the space of darkness thanks to Merlin's Commandment that wants to enter and join the others. Upon entering, they find the cocoon of where Meliodas is. The five are received by Zeldris, Cusack and Chandler. Ludociel, Escanor and Merlin go face to face with Zeldris, Chandler and Cusack respectively, while Hendrickson and Gilthunder are overwhelmed by the presence of demons.
After a hard battle, the Assault Force manages to defeat the three major demons. However, when the spell that kept Mael's memories turned into those of "Estarossa" is broken, the demons see the opportunity to recover. There, Chandler and Cusack decide to merge into the Original Demon.
When the remaining five Commandments are absorbed by Meliodas, Merlin decides to use the forbidden Chrono Coffin to suspend the cocoon in time, leaving Escanor, Ludociel and the recently awakened King, alone to fight against Zeldris and the Original Demon in what she completes the spell.