The Old Ones
5e Rules Changes
There are no spells that will resurrect a dead player. (or at least resurrect them in their normal form).
There are no spells that provide a “pocket dimension” resting space.
There are no spells that remove curses. There are ways to remove curses, but you will have to get creative….
Long Rest does not restore full hit points. It will recover half your hit dice, though. Rounded down.
None of the playable races have darkvision.
Your alignment does not effect the game in any way. Your alignment is a result of your actions, not what you’ve written on your character sheet. Actions considered heretical or in opposition to your religion may negatively affect clerics and paladins.
The only creatures that will be detected as “evil” are the undead and extraplanar abominations.