Turning Feral.

Ghouls need two things to survive and avoid becoming feral radiation and hydration. They do not need to eat and only need rest to Regain lost Hit points. 

Radiation.

The most important thing to a ghoul is Radiation without their bodies begin to decay, their brain tissue begins to deteriorate and over time they become Feral. To avoid this Ghouls must Absorb Radiation From the environment to combat Radiation lost over time. Every hour ghouls lose 2 rads into the environment and theretofore must take 2 Rads an hour to combat this.

Whenever in Radiation ghouls can absorb radiation at a higher rate than humans with the ability to absorb 10 rads by spending 10 minutes in a low radiation area. Ghouls tend to sleep in irradiated areas where possible to avoiding losing Rads as they rest. 

If a ghoul loses all of their Radiation to the environment they will take lose 1 point of sanity every  4 hours 

Hydration 

Ghouls must consume twice as much water in a day as a normal human to avoid becoming feral. This means every day in normal temperature they must drink 2 litres of water and in a hot environment they must drink between 4 and 6 litres depending on temperature. 

If a ghoul does not meet the required  amount of water in a day they will lose 1 sanity point. 

Sanity points.

A ghoul has a number of sanity points equal to their endurance score plus half of their Intelligence score (rounded down) 

For example a character with 7 endurance and 5 intelligence would have a sanity score of 9 points and once the player had lost 9 points the next point lost would turn them feral, the only way to regain sanity points is to not lose 1 for 3 days. 

So a player with 9 lost sanity points, would need to avoid losing a point for 27 days to recover all of the lost points.  

Losing Feral Points.

As You Begin To lose Points Your Dm Will Instruct You To Roll on one of the four Feral Effects Table Based on How Feral You Are. For Each Table Roll 1 D10, If you land on an effect you already Have Re-Roll. 

Table 1.

Roll 1D10 Effect
1 Your Mind is Beginning to slip away, whilst this disadvantage is active your skills all Suffer a penalty of 1D6 points.
2 Your Arms are weak and aching you can No longer use two Handed weapons.
3 You are Begining to Crave Meat, each day you must consume 0.5lb of Meat or roll 1D20 on a Roll of 1 you gain 1 Feral Point.
4 You Are Begining To Develop Dark Vision You Can Now see 10ft as if it were Dim Light.
5 As your Brain deteriorates you Grow Distracted easily, when attempting an action that lasts longer than 1Hour you must Roll 1D20 on a Roll of 5 or less you become distracted and automatically Fail.
6 As you slowly Turn feral you begin to Bite your enemies, you can now use the Bite attack once per turn dealing 1D8 piercing damage.
7 Your Hands begin to Grow stiff moving your fingers quickly is Difficult you can only Reload half of your Clip or charge using an action in combat.
8 Occasionally you lose Focus whilst in combat, at the Beginig of each round Roll 1D20, on a roll of 2 or lower you are Skipped and spend your turn standing still slightly swaying From side to side.
9 As Your body Decays you begin to lose Feeling, you can no longer tell exactly how much damage you have taken during combat, you must spend 5 minutes after combat inspecting your wounds and pass a Dc75 medicine check to determine your exact Hp.
10 Any mention of The war communism or Feral Ghouls scares you Make an Endurance saving throw of Dc100 or Gain disadvantage on your next Roll.

Table 2.

Roll 1D10 Effect
1 You have Developed a Fondness for discarded, useless items and pick them up Randomly, once you've picked up a junk item you cannot bring yourself to put it down.
2 Your Mind is Slipping away, whilst this disadvantage is active your skills all Suffer a penalty of 1D10 (this perk stacks with Lower levels)
3 As Your body Decays your circulation Begins to Slow, The effects of poisons are Now Halved.
4 As you Return to a Primal state your senses increase you now have Advantage to all perception Skill Rolls.
5 Your Dark Vision Has Improved You Can Now see 15ft as if it were Dim Light.
6 Your Hand Eye coordination has Deterorated, all attacks with Ranged weapons over 25ft have disadvantage.
7 You have Developed a serious Fear of Fire, when ever you are within 25feet of a burning object you cannot focus and gain disadvantage to all Rolls.
8 As You slowly turn feral you Begin to lose Yourself after each Rest Roll 1D20 on a Roll of 8 or Lower your Dm will choose 2 Random skills to swap point scores.( if this effect is applied Roll 1D10 to Determine how long it lasts, once you have made a Number of Rolls with either of the swapped Skills equal to your Dice Roll the effect ends, the effect also ends if 2 more skills are swapped.)
9 You are Begining to isolate yourself from others, if you are 40ft or more away from a Team mate you gain advantage on all Rolls.
10 The Light Burns Your eyes your vision when in sunlight or any Bright Light is Reduced to 20ft.

Table 3.

Roll 1D10 Effect
1 Sunlight Burns your Eyes whilst this disadvantage is active, and you are in direct sunlight you have a disadvantage to all attack Rolls.
2 Your sense of Direction is Slipping away, when you move in combat Roll 1D20 if you roll 4 or Lower the Dm will move you in a Random direction.
3 Your Movement is slow and Weak, the penalty for Difficult Terrain is Now doubled.
4 Your Dark Vision Has Improved Further You Can Now see 25ft as if it were Dim Light.
5 It is Now visible to others that you are turning Feral, Humanoid creatures will be wary of you and you may also be refused entry into some locations.
6 Your muscles are wasting away, as a result your Maximum carry capacity has halved.
7 Your Flesh is Beginning to Rot and wither as a result you have Disadvantage on all strength Rolls.
8 Your Mind is Rapidly to slipping away, whilst this disadvantage is active your skills all Suffer a penalty of 1D20 (this perk stacks with Lower levels)
9 Your Blood Has Stopped Flowing, you are now immune to the Bleeding Condition.
10 Your Reaction Times are slowing, you can only attack a maximum of twice per turn.

Table 4.

Roll 1D10 Effect
1 Your Flesh is Beginning to Rot and wither as a result your strength skill is Halved and you have Disadvantage on all strength Rolls.
2 You can regain Hit points From feasting on the Flesh of your enemies. (If you already have the cannibal perk you gain 25% extra Hp).
3 The smell of your Rotting flesh has begun to attract predators, you are now more likely to Be attacked while travelling in the Wasteland.
4 As they are not a valid food source you no longer Notice Robots, while you have this disadvantage all Robots are considered invisible to you even if other players can see them.
5 Sometimes when you speak all that comes out is a Gurgling growling noise. After every speech or Barter check Roll 1D20 on a roll of 10 or less you automatically fail.
6 Your joints have Decayed your tendons have snapped as a Result your speed has been Reduced by 75% (Rounded down to the nearest 5) to a minimum of 5 feet.
7 Your Dark Vision Has Been Perfected You Can Now see 45ft as if it were Dim Light.
8 When you sleep to Recover Hp you seem to attract Feral Ghouls. Roll 1D4 for a four hour Rest and 1D8 for an eight hour rest, (this disadvantage only has an effect if you are in an area ferals can acess).
9 You Drop your weapon unsure of how it works, whilst you have this disadvantage you can only make unarmed Attacks. Dealing 1D6 Damage twice per turn.
10 You have lost the Ability to Speak clearly. Whilst you have this disadvantage Your speech and Barter Skills are set to 0 and you have disadvantage when Rolli g to use either Skill.