This is a per-user difficulty mod made by your's truly, Candi

Note: Please check the changes below to determine whether you should set the keepInventory gamerule on or off.
Note 2: The damage modifiers do not work in PvP. This is intentional.

Changes

0.5.12

Teleports are now more robust and shouldn't cause as many problems. In addition, I implemented /tpz for ops.

0.5.9

/back now also can send you back from where you last /home'd from. Also, minor code improvements.

0.5.8

Bugfixes.

0.5.7

Attempted to fix the bug where /home across dimensions will cause the world not to render until reconnect. I don't know if this will fix it or not, but it won't hurt anything.

0.5.6

Added /home <dimension> to allow you to teleport to any dimension's home. Also added /spawn.

0.5.4

Fixed the bug where non-operators couldn't use the commands.

0.5.3

Added /back command. Tied /home and /back into the difficulty system. Both commands are available if you have not yet set a difficulty level.

0.5.2

Added /home command.

0.5.1

Food and Saturation added. /adminsetdifficulty added to allow admins to change others' difficulty. /setdifficulty will now tell you how long you have until you can change your difficulty again (down to the second). Minor code cleanups throughout. Minor, mostly aesthetic, changes throughout (some messages tweaked, colors in multiline messages now work properly, etc). Also added tab autocompletion for the difficulty levels and for usernames where applicable.

0.3
Inventory saving has been re-implemented. You should keep the keepInventory gamerule *OFF* from now on. This should also fix compatibility with other mods that do things related to death and respawning.

0.2
You should keep the keepInventory gamerule *ON* until the next version when I'll fix compatibility with gravestones and such.

Usage

/setdifficulty <disabled|easy|medium|hard>

This will set your difficulty for the purposes of this mod; this is separate from the difficulty of the server. There is a rate limit on this command such that you cannot set your difficulty more than once every hour by default to prevent abuse (this is configurable). The difficulty you choose is saved between sessions as well. Tab autocompletion is enabled for difficulty levels.

So far, this will affect 5 areas, all of which are configurable in the config file generated when you first start the server.

Damage taken
Damage dealt
Food
Saturation
Keep Inventory
/home and /back

By default, the following is modified:

Disabled

No modifiers at all; this effectively disables the mod for you.

Easy

75% damage taken
125% damage dealt
125% food
125% saturation
Keep Inventory on
/home, /spawn, and /back

Medium

100% damage taken
100% damage dealt
100% food
100% saturation
Keep Inventory off
/home, /spawn, and /back

Hard

125% damage taken
75% damage dealt
75% food
75% saturation
Keep Inventory Off
/home

/adminsetdifficulty <username> <disabled|easy|medium|hard>

Usable by ops of permission level 2 or higher only. Sets someone else's difficulty level. You may not change your own difficulty level with this command. However, this command does override the rate limit, though it will reset the countdown until the person can change their own difficulty again. Tab autocompletion is enabled for both usernames and difficulty levels.

/home <set|dimension>

Allows you to set your home in each dimension and teleport to it at will. Use [/home set] to set your home and [/home] to teleport to it. Again, this only allows one home for each dimension. This command is usable by all difficulties by default.

/back

Allows you to return to the last place you died. Once you return, the location is no longer saved. This command is usable by all difficulties except hard by default.

/spawn

Allows you to return to spawn. This command is usable by all difficulties except hard by default.

/tpz <player>

For ops only. Teleports to player regardless of dimension or location, assuming a valid location (it uses the same teleport rules as the rest of the mod). This is not tied into the difficulty system because it's an op-only command.

Source: Github

Additional features planned

Modify healing rate

Candi's Per-User Difficulty