Customizing a Background

You have to stay within each “category” as I understand it. For example: You can’t drop a skill and pick up another background feature. You can’t trade in your proficiency with a weapon to take proficiency with the skill Perception.

PS-That said: we’re getting down into the nitty gritty of a character. As a GM I never audit a character sheet, unless some player really forces me to by making outrageous claims. I encourage everyone to scrupulously follow the rules … but if somehow you accidentally become literate through the loss of proficiency in gambling tools (cards/dice) I’ll probably never notice it as a GM (or care much if I do).

Yeah. That does muddy the waters.

One part of my thinking says that since there is a statement on this in the Campaign Sourcebook, that would override what is written in the 5E SRD because it is specific to the Arcanis Campaign.

The SRD statement seems to equate Tool Proficiencies with Languages. The Arcanis Campaign Sourcebook has included some Weapon Proficiencies as Background choices (Bodyguard,Veteran) which no PHB 5E Backgrounds did. And the Campaign Sourcebook seems to equate these Weapong Proficiencies with Tool Proficiencies. These are good ones to swap out in a Background, because any Fighter type character will have Simple and Martial proficiencies already. Maybe this is the reason that the Arcanis Campaign Sourcebook made its statement different to the one in the SRD – because the options available have slightly changed.

The way I look at it (which is just IMHO), whether from SRD or Campaign Sourcebook, Features are Features and can only be traded as Features. Skills are Skills and can only be traded as Skills. Then the other bits (Tool Proficiencies/Weapon Proficiencies and Languages/Literacy) are where I am not sure. Would it be legal to trade a Language for a Weapon Proficiency? It would take some pretty fancy rationalisation in the explanation of the Background. I’d stick to Language for Language/Literacy and Tool/Weapon proficiency for Tool/Weapon proficiency. And even then I’d leave the Weapon proficiencies to Veteran/Bodyguard and so on rather than give a character one when he has the Former Slave Background (for example).