A Christian finance worker lost a claim for religious discrimination launched after a colleague dressed as a devil for Parkrun at Halloween.
Elaine Wilson claimed she was being personally attacked when Glyn Williams posted a picture of the costume - which included the pretend race number '666' - on a work group chat.
The devout Christian also took issue with the fact that other colleagues said 'Oh my God' around her, an employment tribunal heard.
Miss Wilson asked her boss to tell colleagues 'not to use the Lord's name in vain'.
She sued for religious discrimination after being sacked for not getting along with her co-workers.
Her claims against Viaduct Care CIC were all dismissed.
The tribunal, held in Manchester, heard Miss Wilson worked in a finance role for Viaduct Care, a federation of GP practices in Stockport, Greater Manchester, from May and December 2023.
Miss Wilson is a devout Christian, who 'described her personal life as all revolving around Jesus Christ'.
The company had open plan offices, but she often tried to work in quiet spaces or rooms.
Elaine Wilson claimed she was being personally attacked when Glyn Williams (pictured) posted a picture of the costume with 666 where the number would be
Mr Williams, pictured without the costume, said 'the whole thing was ridiculous' when asked
In September 2023, she told her line manager Graham Rose that she sat alone because 'people seem to have an issue with the fact that I am quiet and not always chatting in the office, as well as the amount of time people would use the Lord's name in vain.
She added: 'I know it's just a slang word and a part of people's language nowadays, but I do believe that He exists and that it is rude to use His name as just a slang word.'
She asked for her colleagues to be told 'not to use the Lord's name in vain'.
The following month, an email was sent to the team which said: 'Can we all be aware that Elaine is very religious and that some of the colloquial terms that we may consider acceptable in the UK can be offensive to her.
'Please bear this in mind when you are in the office.'
One of her colleagues subsequently complained that she felt religious views were 'being forced upon her'.
Miss Wilson then complained that 'two people used the Lord's name in vain and it seemed to have been on purpose'. The tribunal found that this had not been on purpose.
The tribunal heard: 'On October 29, 2023, it was the birthday of a colleague, and [her colleague Glyn] Williams posted a picture of himself participating in a Park Run dressed in a devil costume with the number '666' as a pretend race number.
'[Miss Wilson] alleged that this amounted to direct discrimination because of religion...'
Two days later, on October 31, Mr Williams posted a picture of him and his wife in Halloween costumes on the team WhatsApp, showing him dressed as a 'zombie'.
It was heard Miss Wilson replied by sending a religious article. The tribunal heard: 'It was a link to an article which she said he might enjoy.
The article was called 'Evil Spirits Used to Terrorise Me. I know what Halloween is …'. It was the testimony of a person hosted on a Christianity website.'
She told the tribunal that the following month, people were being excessively noisy in the office in order to 'get at her'.
A colleague made a complaint about Miss Wilson's behaviour on a coffee morning in a new office - it was alleged that 'some people have decreased their time in the office due to feeling like walking on eggshells'.
Another colleague alleged that it was actually Miss Wilson doing the 'oppressing' and said that they were worried they might upset her 'just by talking'.
This colleague also felt Miss Wilson had 'dogmatic religious views'.
In a review hearing, Miss Wilson said that she 'did not mind if people use the Lord's name in vain but just did not want to sit in a space where she was constantly hearing it'.
She was sacked during her extended probation period, in December 2023.
Explaining her dismissal, bosses said: 'There were a significant number of incidents during your probationary period where your conduct towards other staff members were concluded to be unacceptable.
'You have proposed that these incidents were due to environmental issues, but despite significant support and adjustments, there has been a continued occurrence of incidents.'
Miss Wilson appealed against the decision to sack her, arguing she had been harassed and bullied, but this was dismissed.
Managers said that she had been fired for a 'failure to meet the expected standards of professional conduct'.
On the devil incident, Employment Judge David Franey said: 'Those posts were not directed at [Miss Wilson].
'They cannot be less favourable treatment of [Miss Wilson] because of religion because the posts were for everyone in the WhatsApp group.
'Everyone was treated the same. [Miss Wilson]'s religious views were the reason she was offended by the posts, not the reason for them, and therefore the allegations of direct religious discrimination failed.'
All her other claims were dismissed by the tribunal.
Speaking from his home yesterday Mr Williams said: 'In my opinion the whole thing was ridiculous. But I don't want to comment anymore.'