Does a Character with a Custom Lineage belong to a race, for the purposes of racial requirements?

Question

Tasha's Cauldron of Everything introduces new character options. In the Customizing Your Origin subsection, there is a side panel that details the Custom Lineage options.

This option allows you to, "instead of choosing one of the game's races for your character at 1st level", select among a few options to shape your character's origin.

It is unclear if the resulting character is actually part of an official race, for the purpose of picking racial feats, attuning to race specific magic items, or picking race specific subclasses.

Answer 1

Yes, your race is "Custom Lineage".

In the December 2021 errata to Tasha's Cauldron of Everything, the following sentence was added to the end of the Custom Lineage sidebar

Your race is considered to be a Custom Lineage for any game feature that requires a certain race, such as elf or dwarf

You do have a race, Custom Lineage; but unfortunately, that race does not count for features that require you to be a different race. If any racial feats are published in the future having Custom Lineage as a prerequisite, then Custom Lineage characters will be eligible for those.

Answer 2

Note: This answer is no longer relevant after the release of the December 2021 Errata.

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No, but...

The Custom Lineage sidebar in Tasha's Cauldron of Everything states (p. 8; italics for emphasis mine):

Instead of choosing one of the game’s races for your character at 1st level, you can use the following traits to represent your character’s lineage, giving you full control over how your character’s origin shaped them:

Creature Type. You are a humanoid. You determine your appearance and whether you resemble any of your kin.

This indicates that, while a custom lineage character may look like a certain race, mechanically it is just a generic humanoid. This choice is made "instead of" one of the game's races.

Rules designer Jeremy Crawford has offered unofficial guidance on Twitter which reinforces this (hat tip to pdegan2814's answer for finding this):

In Tasha's Cauldron of Everything, the custom lineage option is chosen in lieu of a race, such as elf or dwarf. If you choose the custom lineage, you don't qualify for things in the game that require elf, dwarf, and the like.

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It is important to realize, however, that race can be a sensitive topic for players and there's a risk of invoking things like Native American Blood Quantum laws or general "racial authenticity" in game which players may have real world experience with.

So, with the aim of preventing negative associations for the players, the DM ought to know his/her audience and be ready to also invoke DM fiat to allow exceptions to what the game mechanics indicate should happen.

Answer 3

Thankfully Jeremy Crawford recently clarified this with an unofficial ruling:

In Tasha's Cauldron of Everything, the custom lineage option is chosen in lieu of a race, such as elf or dwarf. If you choose the custom lineage, you don't qualify for things in the game that require elf, dwarf, and the like.

Short version, if you use Custom Lineage you cannot use racial feats. If you use some of the other options for customizing an existing racial option(like swapping stat bonuses, proficiencies etc) from Tasha's, you're still that race and qualify for its available racial feats.

Answer 4

It is unclear.

However keep in mind that various elements of the 5th edition system are actually setting details. By necessity the authors of 5th edition wrote in an implied setting within the rules to make the system more useful to its buyers. This included things like the different damage types (piercing, necrotic, radiant, etc.) and tying a magic item to a race or culture.

In your case whether a magic item that is limited to Dragonborns works with a custom lineage is dependent on what the referee (DM) of your campaign says.

I would expect that if my custom lineage is a variant of the Dragonborn race then the answer would be yes. Magic items that work only for Dragonborn will work for your character if you designed your custom lineage to be a Dragonborn variant.

A possible issue that may come up is a disagreement over at what point changes in the mechanics of lineage makes it obvious that the character is not part of that race. If the customization is similar to the current race variants then the answer would likely be "Yes the character is a member of the race."

Here is an example of keeping most of the traits listed under elf in your workup of a custom lineage.