The DM should not unilaterally alter core setting details for a single player without consulting the group.
Significant changes to core lore, if made at all, should be made in good faith with the buy-in of the group.
Handle the problem honestly but directly:
"I understand that your character is not evil, but this character concept is not a good fit for our particular game."
If this is a personal issue for the DM (e.g. she finds she just isn't comfortable with undead of any sort) then she should say so:
"I'm not comfortable with necromancy in general, so I don't include it in my settings. It's a personal boundary for me, I hope you can accept that."
The 5E DMG specifically grants the DM the role of world-building
The DM is expected to set restrictions in order to develop the world.
The first part of the 5E DMG is Master of Worlds. The Introduction states:
Every DM is the creator of his or her own campaign world.
CH1:
It is up to you [the DM] to decide where on the spectrum you want your world to fall [from the baseline assumptions when running an existing setting].
On Page 26, the DMG suggests that the DM compile a handout for the campaign that includes:
- Any restrictions or new options for character creation... [emphasis mine]
- Any information in the backstory of your campaign that your characters would know about.
DND 5e explicitly grants the DM the ability to define the world. The first 70 pages of the DMG are dedicated to this task. It is expected, as part of the game, that the DM has the authority and ability to define character creation restrictions as well as the world and how it operates.
This is part of the trade-off taken when agreeing to DM: The DM has the responsibility to develop and manage the game, but the freedom to shape the world.
The Setting is the the DM's Character
When a player asks the DM to change core lore, they are impeding on a role explicitly given to the DM. Nothing in the DMG suggests that players can demand changes to the setting, just like a DM cannot force a player's character to take any particular action.
Group consensus is more important than a single player's character concept
An RPG is a social project where players and the DM work together to develop a world, story, and setting. When a DM pitches a game, it usually involves a particular understanding of how the setting works.
This setting requires buy-in.
For a group to be successful, everyone needs to be on the same page with their game. Fear the Boot's Group Template is example of constructing a common consensus around the game in a structured way.
When the DM presents a world, and players agree to participate, the DM has organized a group around a common goal, vision of the world, and mindset.
When a single player asks for substantial modification to the game world after the setting is established, this affects the entire group, not just the DM.
If the players have already agreed that this is not a setting where walking skeletons are an everyday occurrence, this player's request is a challenge to the game as a whole. If the DM wants to consider this player's proposal, she should discuss the idea with the group before making the change.
This situation has already escalated.
Your DM looks like she's handled this challenge to the game in a firm way. Your fellow player is apparently harboring a grudge and refusing to change their concept.
A fundamental table rule is (DMG 234):
- Respect: Don't bring personal conflicts to the table or let disagreements escalate into bad feelings
The player's reaction is to let the bad feelings linger. The player, instead of discussing the disagreement further, both accepts and rejects the DM's decision. I read their particular response as:
"I accept that my character concept will cause problems, but you could remove those problems, therefore you are to blame for them."
This particular player is couching long-term resentment in conciliatory terms. This behavior is a red flag. It is a misleading response and does not show consideration for the game as a whole.
Unless the group decides this matter collectively, the game will have a built-in interpersonal conflict before the first session begins.
It is important for the DM to resolve this tension before the first session
Like above, respect is the key starting point:
"I know we had some disagreements about your character concept. I generally don't think necromancy could work in this setting. Do you have any ideas for how we could make it work, or what else the character could be like?"
The player may propose a more subtle approach (only raising dead in the dungeon, not bringing them to town). Or the player might stay adamant and demand that they have undead servants in town.
The outcome of this conversation is either:
The DM finds a compromise that fits her expectations, and does not alter the setting too much while finding room for this character concept.
The player understands the game world better and designs a more appropriate concept
The player refuses to cooperate at all, and then a more difficult discussion has to be had about whether they are a match for the game.
I actually had a player do this in my game! He wanted to play a necromancer, but I didn't want undead roaming our city. He suggested that I give him a bag of holding as his starting magic item. He takes some time to unpack a skeleton he animated when needed, and I don't have to RP people terrified of skeletons all day. This fit my game (it's a bit outlandish) but was a win-win for both of us.
In my case, though, my player was immediately willing to work with me and compromise. I could have told him "no." He would have made a different character without hard feelings.
Games are always a compromise. These compromises need to be made in good faith, with respect for each others' boundaries.
Sources:
- 5e DMG
- 17 years of GM experience
- 18 years of RPG experience
- Fear the Boot RPG podcast