Friends, Faerûnes and Dungeon Masters, lend me your ears. I ,with the premission of my DM, have created a character who cannot be killed. However that does not mean there aren’t consequences for death. Whenever this happens the DM rolls a d100, applying a boon or curse from a list.

Originally my idea was a 50/50 split but my DM suggested either a 70/30 or 80/20 curse to boon ratio. I’ve settled on 75/25. Here’s where I need some help, as I have bitten off more than I can chew.

First I have based this off rolling a d100 would 5d20s be better or just a d20(reducing the total number of boons and curses I need to come up with?

Second as for boons and curses I was thinking max/min ability scores at the high and low ends. Being blinded or cursed with berserker so they have to attack the closest character. Being blessed so they have advantage on rolls.

Any thoughts or suggestions would be of great help.

Why would they get a boon from dying?

Narratively speaking my devil may bestow a boon because they feel i may need additional help since I've died.  

If I were your DM, I would let it be just a D20 because I know the pain of having to come up with 100 interesting things. Also you might need to remember, death is traumatizing and after a certain point your character would figure out that adventuring just isn’t worth it anymore. I was bored so here are a few suggestions for the D20 roll. Maybe toy around with the idea of neutral effects, that don’t affect your ability to do anything, but change your character nonetheless. 

Get blinded or deafened (DM’s choice) if this result comes up more than once, reroll

You have a single extra fifth level spell slot, but once used it can not be recovered until you roll this result again

You come back to life and you realize your hand is searing with pain. You can only watch in horror as the flesh of your hand melts away, revealing the bone underneath.

You realize that something feels off as you return to the world of the living. Your body has switched genders! 

If you need more ideas, the Sibriex flesh warping table in MotM has some interesting results to say the least. 

Yeah man thinking of a 100 different things was a brilliant idea until I had to actually think them up.   

Thanks for the suggestions I liked them..I was thinking of having some options where I begin to turn into a tiefling, like getting horns or my flesh turns red, so the body dysmorphia is an cool idea.  

As for death being a traumatic event, for this character it's not, they are generally unhappy so they would prefer death sometimes.  Also I view ot kind of like that Tim Cruise movie Edge of Tomorrow, where death is more of a learning lesson.  Also my plan isn't to just put myself in a position to die, as a warlock I'd be more of a ranged attacker. So my hope is my deaths, if any, are more situational.  

lol. I've since switched to just 20 with 5/15 split boons/curses.   Please forgive me but what is RAW?  As for how I will play blind, mostly it would be roleplay but in combat I believe my attack rolls are at disadvantage and attacks against me have advantage.  I'll have to check that again.   

RAW stands for Rules As Written. For example, let’s see a conversation between a rules lawyer and a DM that I may or may not have had last week. 
DM: Alright [PC], the antagonist from your backstory is up on a pedestal, preaching to the crowd about their god, who only you know is fake. Oh you want to eldrich blast their face in, alright roll to hit. 
Rules Lawyer: Um Acshualy, first they need to roll stealth and compare it to the passive perception of the villain to determine if they are surprised or not. 
DM: *ignoring* alright a 18 hits so they fall back in surprise as this bolt of energy seems to materialize from thin air to hit them straight in the chest. They look around, trying to figure who did it…
Rules Lawyer: But in RAW spellcasing is a very loud, noticeable thing thing. 
It goes on like this for a while. 

Gotcha.  Yeah I'm playing with a bunch of long time friends so we don't get to hung up on the rules, if it's for something fun.  This is definitely the most rule breaking we've done but my DM thinks it'll be fun especially with some of the curses I've come up with.  

Thanks everyone for your response it helped a lot.   Here is the final list.   Basically how this works is, when I reach 0 HP, a hole opens up and swallows me, DM rolls a d20 to choose the effect, then on my next turn a hole opens up and I return.   

DM rolls a d20 upon death

20 CHA increased to 20 if already 20 then increase to 22.

19 Can Fly.

18 Feat - Flames of Phlegethos

17 Given a Hellfire Longsword.

16 Dark One’s Blessing – Temp HP equal to total HP

15 Blessed -When you make an attack roll or a saving throw, you can roll a d4 and add the number rolled to the attack roll or saving throw.

14 Grows horns and a tail. (permanent)

13 Blind

12 Upon return to the mortal plane, the dominant hand, wrist, and arm up to the elbow are engulfed in an infernal flame burning away all the flesh, leaving only bones. (Still usable as a normal hand)

11 Curse of Missile Attraction - Whenever a ranged weapon attack is made against a target within 30 feet of you, the curse causes you to become the target instead.

10 Cursed -When you make an attack roll or a saving throw, you can roll a d4 and subtract the number rolled to the attack roll or saving throw.

9 Curse of the Nine Hells – All enemies with any Evil Alignment are compelled to attack you.

8 Festering Wound. Your hit point maximum is reduced by 1 every 24 hours the wound persists. If your hit point maximum drops to 0, you die. The wound cannot be cured.

7 Skin turns red (permanent)

6 Madness of Demogorgon – There is only one solution to my problems: kill them all!

5 Tortoise Bane – You are sluggish. Your speed is halved. When you roll initiative, treat the roll on your d20 as a 1. You can’t change your initiative by any means.

4 Hunter’s Hex – Enemies within 10 feet of you are compelled to attack you. They deal an extra 1d6 damage and an extra 1d6 necrotic damage.

3 Golem’s Curse - Aversion of Fire. If you take fire damage, you have disadvantage on attack rolls. Berserk. Whenever a critical hit is made against you, you to go berserk. On each of your turns while berserk, you attack the nearest creature you can see. If no creature is near enough to move to and attack, you attack yourself. (Last 6 turns)

2 Changes into Tiefling (permanent)

1 CHA reduced to 5

I know I'm a bit late to this, but I do wonder at the randomness aspect? I mean, even 20 possibilities seems like a lot – how often are you expecting to die in the campaign?

Personally if I were your DM I'd just create a shortlist and decide which makes sense depending upon the circumstances of the death; for example, if you died trying to fulfil the terms of your contract against impossible odds, then a boon makes sense, like a rod of the pact keeper. But if you died trying to backflip off a horse which proceeded to kick you to death, you'd better believe the penalty is having a permanent hoofprint on your face that cannot be removed by any means. 😝

I think it's good to have the shortlist of possibilities for the DM to choose from though, like turning into a tiefling is very thematic, and seems like a logical progression from the "skin turns red" option if you mess up twice. But yeah, I guess I don't see the benefit of it being random really as you could end up being punished for dying trying to do the "right" thing (as determined by your pact) or rewarded for eating a steak too fast and choking to death.

Also I would 100% have an "end of arc" option on the back-burner at all times where you can choose to die permanently in order to bring someone else back, but now they're bound by your pact. Could be great if more than one character dies to something really tough.

Well originally in my mind I wasn't planning on dieing a lot, as a warlock I'd be more ranged spell attacker.  I figured my deaths would be more situational.  But after showing my DM a partial list, he liked a curse that made me a target so that it was like a boon to my companions even if it's a curse for me, roll of 11 specifically.  So now I think I may die a lot depending on the roll.  

Well first session went down as well as you would expect.  I died in the first encounter and my DM rolled a 2 which turned me into a Tiefling.  Thus negating the rolls that made me a partial Tiefling. I'd would change those if I do this again.   My DM decided those will just be rerolled if he gets them.  

The group is definitely freaked out by the mechanics of this character especially since they met me and I was. High Elf and now I'm a Tiefling.