Unlimited Hit Dice? (balance check)

[TheCosmicKid]

So I had an idea for a new ranger capstone ability:

Iron Ranger

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At 20th level, you are an indefatigable wanderer-warrior. You are immune to exhaustion, and you have an unlimited number of Hit Dice. (This does not increase your hit point maximum.)

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So obviously, giving a player an infinite amount of a normally-finite resource sets off all sorts of game design alarm bells. But the thing is, if you can get away with it, that's what makes the ability so exciting. And I can't think of anything in the core game that you could abuse with unlimited Hit Dice. I just wanted to ask: am I overlooking something?

 

[Xeviat]

High level fighters get regeneration up to 1/2 HP, and can use their second wind to heal up to full with a few short rests. This means the ranger will refill HP after every short rest, up to full unless they were really beat down, instead of after every long rest. As long as you aren't playing in a game that uses variant rules that let you use HD to power offensive things, I don't think it's the worst thing in the world. It might be a smidge strong, and it won't help them within a single fight so it doesn't really boost their "CR".

I like it, and I don't.

 

[FowlJ]

Not really a balance comment, but are hit dice used for something other than healing that I can't remember at the moment? Because this seems like a less elegant way of saying 'You recover all your hitpoints when you take a short rest'.

 

[Oxydron]

Not really a balance comment, but are hit dice used for something other than healing that I can't remember at the moment? Because this seems like a less elegant way of saying 'You recover all your hitpoints when you take a short rest'.

Indeed, just regenerate all your life on every short rest. Maybe get a passive regeneration per turn too? Like one hit die per turn.