In the worlds of DnD there is a certain set of rules for lost limbs and prosthetics.
While is something more or less rare, it could add something new and intresting for the game. (if not allready planned)
For example, you could sacrifice one of your arms in one act of helping in a quest very early in the game. For example pulling out a child from a burning building where no options are left to recover it in a safe way.
You find yourself in a situation of survival with little to no means of food. Struggling to live and feed yourself, you find a magical beast in the same situation in the same area. You could kill and eat it. The beast so weak it allmost cannot defend itself. Or you could sacrifice your leg and offer it as food for the beast.
Dealing with the underground wheels, thievery and lords of drugs and crime. You betray them / you work with them- and the punishment for that ? You can choose yourself. Be it your arm, be it your legs?
This would create another background for your character and dialoge options for some of the best and the worst smiths, trader of high and rare quality, legendary mechanical craftmanship from the gnomes, undead arms from hidden necromancers or just a wooden replacement or the typical hook arm from the carpenter as the first step.
Maybe you have to sacrifce the most important part of your character, be it your right arm (or left arm, not to punishing) for the fighter, the leg for a rogue or monk and only these classes can sacrifice limbs.
It would open your personal questline to improve that limb as you progress.
You maybee sacrifice early game power for lategame scaling (the magical beast returns a great gift to you, the child was a kid from a mighty noble, you gain massive respect and reputation among the people for betraying the crime lord or befriedning with him and be punished by the law)
You could get situational strong early game power (summoning the magical beast), but beeing weaker on longer fights without the ability to rest and regain the ability to summon one beast, once a day.
It could give you dialoge options to beg, to persuade, sacrificing will not stop you to achive what you want.
There could be limbs linked with items that only such a person can use. A legendary crossbow arm, only for those who walked the path of sacrfice.
The beast returns and brings you the claws of a dragon.
Your undead leg gives you the ability to kick the enemy as a free or bonus action with necrotic damage after you attacked your enemys.
Forgive me for my rusty english skills.
This is just some kind of idea that could be really cool and depending on the way you play and the paths you choose.
Or DLC giftbag worthy