Variant Rules (Batheron's Heel Supplement)
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The resting rules in 5e represent a much more forgiving system, where you can just sleep off most of your wounds. Batheron’s Heel is made to be, or is at least trying to emulate, something much grittier.
Types of Rests
There are now three types of rests. Quick Rests, which last one hour, Short Rests, which are eight hours of sleep, and Long Rests, which are three days of uninterrupted rest, including light activity if you so choose.
A quick rest is an hour of light to no activity. After a full Quick Rest, anyone who took part may expend one hitdie, and regain that amount of hitpoints.
Short Rest Changes
Any feature which would effect Long Rests and sleep, such as Trance or Living Construct, now effect Short Rests.
A maximum of 20th level is made for a much higher fantasy than this.
The maximum level for any player character is 10th, and the experience requirement for every level is doubled, as shown below. However, Epic Boons can be gained at 10th level, following normal rules.