The RuneQuest game is a low magic-oriented game. It assumes that everyone has access to a certain amount of magic. Standard Christianity, however, teaches that magic and sorcery is evil and is not compatible with Christianity proper. How to overcome this problem?
I assumed that Christianity as a single all-encompassing religion is unsuitable for game purposes. Therefore, I went for Saint Worship as a solution.
In the Alternate Earth I was planning, Christians worshipped Saints in the same way that pagans worshipped their own gods. So, I treated Christianity as a Pantheon of Saints, bound together more tightly than normal pantheons, but a pantheon all the same. This meant that soldiers could worship a martial saint such as St. Michael or St. George, Healers could worship St Brigid or even Mary. It also fitted with the idea of Patron Saints and with the Catholic hierarchy as I saw it.
Thus, Saint George is the Saint of mounted knights. He grants True Spear, Shield, Bladesharp and Protection and teaches Spear attack, Shield Parry and Ride Horse. St. Michael would grant Shield, True Sword, Fire Blade, Bladesharp, Protection and Strength and would teach Sword Attack and Shield Parry.
I had a list of Saints who existed before the 4th/5th century AD and what their functions and powers were supposed to be - what miracles they had performed, who they were patrons etc. I used this to create a sketch cult for each of the major saints. Unfortunately, this is all in Ireland, unless I have lost it, and cannot be reproduced here. It is fairly easy to do, though.
This would not be important, save for the fact that during the Age of Arthur several Saints were alive and practising. St Patrick and St David were around, although at slightly different times. St David had, I believe, a Saint teaching him and maybe had another as a friend, but I cannot remember their details.
Saints may call for Divine Intervention from Source, at normal cost. This can perform miracles over and above the norm.