Here's how I would do it:
1. Create a table for the "items" you want to document with at least 2 columns:
a) ItemID, Autonumber, Primary Key.
b) ItemName, Text.
2. Create a table with all the "attributes" ("Marvel", "DC", "character", "vehicle", "alien", etc.) with also 2 columns (at least):
a) AttributeID, Autonumber, Primary Key.
b) AttributeName, Text.
3. Create a junction table with also 2 columns (at least):
a) FK_Item Number (Long), Foreign Key to the "items" table.
b) FK_Attribute, Number (Long), Foreign Key to the "attributes" table.
The Primary Key for this table is composed from both columns.
4. Each time you want to allocate an "attribute" to an "item", you create a row in the junction table receiving a copy of the primary keys from both tables ("items" and "attributes"). If you want to remove an attribute for an item, you delete the row in the junction table for that "item"-"attribute" association.