Health regeneration

Natural regeneration is not a flat trickle. There is a timer counting up every tick since your last hit, a rate derived from that timer, and a counter that fills at that rate and hands you one point of health each time it tips over. Taking any damage resets the timer to zero.

That reset is why constant chip damage leaves you with nothing back between attacks, and why five quiet seconds behind a wall are worth more than they look.

The base rate is your maximum health divided by 400, multiplied by 0.85, plus 0.15, and then multiplied by a ramp value. The ramp is where the real variation lives. It starts at zero, rises by one every five seconds for the first thirty, then by one every ten seconds, and stops at nine after a full undamaged minute.

So the first five seconds after a hit return nothing. Thirty seconds gets you two thirds of the way to the ceiling. The maximum health term matters too: a 500 health character recovers over three times as fast as a fresh 100 health one at the same point on the ramp, which is a quiet second reason to keep eating crystals.

Movement multiplies the base rate by 0.5 and standing still multiplies it by 1.25, so the gap between walking and holding position is a factor of two and a half.

What counts as moving is narrower than you would expect. Only horizontal momentum stops it, plus being pulled by a grappling hook. Falling, rising and using items all count as still, so you can fire a weapon at full regeneration rate as long as your feet are not carrying you sideways. Resting in a Bed, or on any seat, adds another 1.3 on top of that, which is the fastest passive recovery available with no gear at all.

From Expert Mode upward, the entire natural rate is halved unless you have Well Fed or one of its upgrades. That is the single largest multiplier in the chain and it applies before buffs are added, which is why food stops being optional the moment you leave Classic. A Shiny Stone softens the penalty from a half to three quarters, but it does not remove it. Cook something and keep it running.

Regeneration from buffs and accessories is added at the very end, after movement, rest and difficulty have all been applied. Two useful things follow from that ordering.

First, buff regeneration ignores movement, so a Campfire and Heart Lantern pair pays full value while you sprint circles around a boss. Second, life-draining debuffs cancel most of it outright rather than subtracting from it: a single stack of Poisoned wipes the buff contribution to zero and then subtracts on top.

• Timer freezes. Bleeding and Obstructed pin the ramp at zero, so natural regeneration never begins. Neither does any damage, and they are still among the worst things to fight through.
• Rate multipliers. Feral Bite halves the base rate and stacks with the Expert Mode penalty.
• Flat drains. Poisoned, On Fire!, Frostburn, Cursed Inferno and the rest subtract fixed amounts and can push the rate below zero, at which point the counter runs backward and takes health instead.

The Honey buff answers the third group. It lifts a negative rate up by four before anything else happens, then adds two more and speeds the ramp along, which is why a shallow pool of honey in an arena is worth the awkward movement. Bottled Honey carries the same effect when a pool is not practical.

Stop moving and stop using items, and the Shiny Stone does something nothing else on the list does: it removes the ramp cap. Instead of stopping at nine after a minute, the ramp keeps climbing toward a maximum of 38, and if you have been undamaged for a second and a half it fast-forwards the timer straight to the thirty second mark. It also adds a flat four and multiplies the base rate by 1.1.

A 600 health character standing still with it in Expert Mode lands around 30 health per second, which outpaces most attrition damage in the game. The catch is the condition: any real horizontal movement or any item use switches it off, so it is a between-waves tool, not a combat one.

The stack that pays off: a Campfire and Heart Lantern at each end of the arena platform, honey underfoot if the fight allows it, a Regeneration Potion before the pull, and Well Fed running at all times. Between waves, sit on a Wooden Chair rather than standing next to it. In the accessory slot itself, a Charm of Myths gives regeneration and a shorter healing potion cooldown together, which usually beats the Band of Regeneration it upgrades from.