This plugin allows control over PvP using permissions and permission groups.

The plugin adds the permission pvpcontrol.deny.(Any Number) which denies pvp between any players/groups that share this permission.

The plugin also adds the /duel command, which lets players request duels even if they both have the same pvpcontrol.deny permission.

In order to use this resource I recommend using LuckPerms, to assign permissions. Simply add the pvpcontrol.deny.(AnyNumber) permission to whatever group or player you want to prevent from damaging other players/groups with the same permission.

Do /duel request (PlayerName) in order to request a duel.
Do /duel accept (PlayerName) or click the request to autocomplete the command in order to accept the duel.
The duel will end if either player dies or if both players use the /duel cancel command.

The plugin has only been tested for 1.18.2, but it should work for 1.13+