Hearts of Darkness (Merciless) is one of the 7 Continuation Stages that the player can access after beating An Elder Secret (Merciless), the only stage in Growing Strange. Completing this stage yields an Elder Catfruit Seed, or at a 1% chance, an Elder Catfruit.
- 1 Dark Otter spawns after 6.67 seconds200f.
- 1 Tackey spawns after 23.33 seconds700f.
- When the base reaches 99% HP:
Additionally, you will also want someone good for damage, as pure crowd-control only helps so much in this stage; as for the Tackeys, you can either lure everyone else close to your base by isolating your first bunch of units, stall them near the base while the Tackeys approach and then kill Razorback as soon as possible, or you can use the length of the stage to "tank" the pushback caused by the Tackeys and kill Razorback afterwards. Once Razorback is dead, you have basically won.
- Prior to Version 8.0, Razorback was buffed to 150% instead of 100%, there were 11 Shadow Boxer Ks in total instead of 7, and the boss fight included a third Tackey that spawned 33.33 seconds after the first 2.
- The English name of this stage is a possible reference to the 1899 novel Heart of Darkness.