A custom plugin is currently being coded for RunescapeMC. It will include the following so far:


Skills


Attack, Strength, Defense, Fishing, Cooking, Mining, Ranged, Fire Making, Thieving, Wood Cutting, Agility, Combat Level, Blacksmiting, and fletching.


Combat


For attack, strength, and defense, command to type for an example /attack (switches to attack mode for xp in the attack skill), /strength (switches to strength mode for xp in the strength skill).


Fishing


for fishing percent chance of catching a fish depending on the item fishing with, for an example:
If fishing with a level 20 Fishing Rod (actually a stick in vanilla just custom name and texture) than 5% chance of catching a Pike (pike being redstone in vanilla) upon right click on a set point block


Item Restrictions
also for item restrictions, requirement of being level "x" in attack to wield the weapon, and requirement of being level "x" in defense before equipping certain items into the armor, also strength will be used as a damage modifier, for an example every "x" or "5" levels until level "99" increase players damage permanently by 0.5, also for magic for armor & weapons. Defense increasing players health by 0.5 per "5" or "x" levels until level 99 cap


Magic


Magic require "x" level before using certain commands, requires a level 20 in magic before typing "x" command or a "fireball" as well as consuming items upon usage of commands.