Nylocas Room Mechanics

Theatre of Blood

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Intermediate

Overview

This guide explains the underlying mechanics of the Nylocas room, detailing how its waves and boss function. Understanding these mechanics provides the necessary background knowledge to recognize how and why strategies are built and executed.

Role-specific strategy guides for the current meta across different scales can be found on the ToB guides page.

Waves

There are 31 waves of Nylocas, which are always the same across encounters. Each wave spawns up to 6 Nylocas across the three lanes (east, south, and west) leading to the center of the room.

The Nylocas spawned in each wave are detailed in Appendix ?.

Nylocas

Styles

Nylocas spawn as one of three styles—magic, ranged, or melee—and in two sizes: small and big. When big Nylocas die, they spawn two small Nylocas (called splits to distinguish them from wave spawns), each of a random style.

Nylocas can only be damaged by attacks of the same style as their current style. If a player attacks a Nylocas with the wrong style, that player can no longer damage it. This is called nulling. In Hard Mode, attacks with the wrong style additionally reflect damage back to the player.

Some Nylocas flicker—change style—as they walk down their lane. This starts at wave 16, and every following wave has at least one Nylocas that flickers^[?]. Flickers switch style after passing the lane's halfway point, hold that style for 2 ticks, then switch to their final style (which may match the original).

Behavior

After spawning, most Nylocas path toward one of the four pillars in the room to attack it. Each wave-spawned Nylocas always targets the same pillar in every encounter. If a pillar is destroyed, its collapse deals significant damage to all players in the room, and the Nylocas that were attacking it start attacking players instead.

Some wave-spawned Nylocas attack players instead of pillars. These are called aggros. As with all spawns, aggros are fixed across encounters. Splits from bigs cannot be aggros.

All Nylocas (wave-spawned and splits) naturally explode once they have been alive for 52 ticks (31.2 seconds). This explosion damages players in a radius around the Nylocas.

Demi-bosses

In Hard Mode, waves 10, 20, and 30 spawn a Nylocas Prinkipas (demi/prince) alongside their regular Nylocas. Demi-bosses have the same mechanics as the main boss. Refer to the Nylocas Vasilias section for details.

Room cap

There is a limit to how many Nylocas can be in the room at once. This is called the room cap. From waves 1–19, the cap is 12 in Regular Mode and 15 in Hard Mode. At wave 20, the room cap increases to 24 in both modes. Players refer to this as the cap increase wave.

All regular Nylocas—small and big, wave-spawned and splits—count as 1 toward the room cap. Demi-bosses count as 3 Nylocas.

If the team is at or above the room cap, new waves of Nylocas do not spawn. A failed spawn is known as a stall, which is explained further in the Stalls section.

As the cap is dramatically different before and after wave 20, strategies used by teams change between these two phases. Players call these phases the pre-cap and post-cap.

The room cap counts Nylocas from the moment they spawn to the moment they despawn—not their death. Death animations can be delayed by various factors, which can influence whether the cap is exceeded or not. Death animation timing is explained in Appendix ?.

Room cycle

The Nylocas room operates on a repeating 4-tick (2.4 second) cycle. Understanding this cycle is essential to running the room efficiently.

Cycle definition

The Nylocas instance uses an absolute tick counter beginning when the first player enters the Nylocas area from the Bloat room. Wave checks are offset by 2 ticks from the absolute tick, so checks occur on ticks 2, 6, 10, 14, ...

In practice, plugins and players track a room cycle relative to the wave checks, where cycle tick 0 corresponds to absolute tick 2. The cycle then repeats every 4 ticks:

Absolute	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	...
Cycle	2	3	0	1	2	3	0	1	2	3	0	1	2	3	0	1	2	...

Stalls

Waves only ever attempt to spawn on cycle tick 0. The first wave always spawns on the second cycle after starting the encounter. Due to this, starting on cycle tick 0 is optimal, as it allows the first wave to spawn on the next tick 0 (the fourth tick of the room).

Two things can delay (stall) the next wave:

Natural stalls are a built-in delay between waves to give players time to deal with the previous wave, expressed as a multiple of cycles. A new wave does not spawn until the previous wave's natural stall has passed. The natural stalls for each wave are listed in Appendix ?.
Room cap stalls (always referred to as just "stalls") occur if the room is at or above the room cap on the tick a wave is due to spawn. When this occurs, the wave does not spawn, and the room will check the cap again on the next cycle tick 0.

The cycle of the room can be observed using the ToB QoL plugin by ticking the Instance Timer option under the Nylocas section. It displays the current cycle tick (0-3) before entering the room, allowing players to start the room on the optimal tick 0.

Avoiding stalls

Proficient teams manage the room cap to avoid stalling by prioritizing which Nylocas to kill and timing those kills around the wave spawn checks. Wave management is often less about total DPS and more about controlling when new Nylocas spawn and despawn relative to the checks.

During pre-cap, teams are strategic about which Nylocas to attack and which to ignore. In post-cap, the focus generally shifts to killing bigs quickly to get their splits out early.

Several techniques are common among Nylocas waves strategies:

Prioritizing newer Nylocas and allowing older ones to expire naturally.
Timing the popping of bigs such that their splits appear right after a spawn check, giving the most time to deal with the splits before the next check.
Prefiring Nylocas in the lane from specific positions to control projectile travel time, ensuring the despawn occurs at a desired time^[?].
Particularly in pre-cap, playing around natural stalls by popping bigs when there is a longer delay between waves.
Managing weapon attack cooldowns to align with the room cycle.