Each superior has its own chance at a heart, set by the Slayer level of the superior itself, never by combat level. That is not always the level needed to get the task: only elder custodian stalkers (76) have a superior, and basilisk knights (60) have a better one than regular basilisks.
chance per superior = (1 + superior modifier) ÷ ( 8 × (200 − ⌊(slayer level + 55)² ÷ 125⌋) )
That reproduces all 38 published imbued heart rates on the wiki exactly, from crushing hand at 1/1376 through to colossal hydra at 1/160.
Superiors themselves appear on 1 in 200 regular kills, 1 in 150 once you claim the elite Combat Achievement tier, and 10% better again inside the Wilderness, giving 1/180 or 1/135. Only jellies, dust devils and abyssal demons can be killed there.
The Wilderness cave is faster on both axes. Superiors spawn 10% more often there, and the packs are dense and aggressive enough that kills run about 25% quicker than the same task outside. Those three tasks therefore carry two kill rates, and ticking Killing in the Wilderness swaps to the faster one. What the numbers do not price is the risk: a PK death costs time and risked gear, so if you keep getting caught, type your own rate into the card.
Quantity never changes your heart rate. It only changes how long you are locked at that rate. That is the whole trick: a long task is a gift when the rate beats your baseline and a tax when it does not, which is why a positive quantity roll is good on smoke devils and ruinous on venators.
Two numbers here are estimates rather than facts. Kills per hour is now calibrated to your pace, not to a theoretical one. You timed 3 dark beasts in 90 seconds on 2026-08-08, which is 120 an hour against the 130 this page used to assume, so that one figure carries the yours tag and every other task was scaled by the same 0.92 and rounded to the nearest 5, which is what scaled means. A single measured task cannot capture how much slower a cannon rotation is than a blowpipe one, so treat any individual row as roughly right rather than exactly right. Slayer XP per kill equals hitpoints, so you can measure any of them with kills/hr = slayer xp per hr ÷ monster hitpoints and type it straight into the card. Your baseline is solved by simulating 40,000 assignments against your Slayer level, blocks, task choices and spawn rate, then iterating until it matches the rate that policy actually achieves. It is a mean, total time divided by total hearts, because you spend very unequal time per task. Everything else on this page is exact.