Mors Gloria Salvete Satanas in Lockwood and Co have an evil meaning. Hail Satan here is used to show dedication to Satan (evil). 

There is no specific meaning to the phrase in the dictionary, as it is presented as some evil mantra to attract people into the darkness.

The phrase is said to be in the Latin language in My Memory Translated. 

In the series, this term is used in the third episode when Lockwood and his team go to Combe Carey Hall to solve the problem of the ghost.

John Fairfax offered them the deal to pay 60 grand if they got rid of the problem. 

This episode follows the story from the first book, The Screaming Staircase. The team agreed to the job because they needed that money.

However, when they went there, they almost landed in trouble. When they were checking out the property, Lucy locked ghosts after hearing the manta Mors Gloria Salvete Satanas. 

They had found the staircase by that time. As they got down the staircase, they started hearing the chants, from which they concluded that monks had passed away in that place. 

As the chant continues, a dark shadow starts to form. The two bodies fight with them, but Lucy gets ghosts locked and starts to get visions of her jumping from a high place. She was about to jump in a well but luckily got saved by Lockwood and George.

But, she found the source of evil in residence- the well. There were remains of the human body deep inside the well, which is said to be that of monks.

They bombed the well and got out of the place until they faced Fairfax waiting for them outside with a gun. 

Lockwood and Co follow three teenagers Lucy Carlyle, Anthony Lockwood, and George Karim. They are the agents of a psychic detecting organization that fights ghosts in London. 

The ghosts are referred to as visitors throughout the series. They go out each night to hunt and battle the ghosts. Many adult group organizations offer such services, but Lockwood & Co., run by Lucy, Anthony, and George, stands out the most.

The trio starts their new life free of financial motivations and adult supervision. They are destined to solve a secret that will alter the course of history.

The series was released on Netflix on January 27, 2023. There are eight episodes, and they follow the plots of the first two books, The Screaming Staircase and The Whispering Skull. 

The viewers are satisfied with the show as it has a 7.6 rating out of 10 on IMDB. According to Express Co Uk, it has already topped the Netflix chart this week. 

One viewer wrote that she had not read the book but watching the show was enough to make her fall in love with the story.

The mystery has kept the viewers engaged, and each character develops over the course of the season. They have so much depth in their backstories, opinions, and personalities. 

Likewise, people loved the actors in the show. Ruby Stokes plays Lucy, Cameron Chapman, as Lockwood, and Ali Hadji-Heshmati as George. Their performances in the series have been praised a lot on the internet.