Final Swarm ghost phases — Purple and Red post-boss tuning

After the Wave 8 boss, Final Swarm enters a phased post-boss swarm: Normal (0–6 min), Purple (~6 min, 1.6× pressure), Red (~12 min, 2.4× pressure). Each phase multiplies the boss burst damage, and the priority picks shift from Holy Trinity to Lifesteal + Defense + Movement Speed. This article walks through each phase, the recommended picks, and why Tank Sustainer is the only viable build for the Red phase.

The three phases

The pressure multiplier scales the boss burst damage. A build that survives Normal pressure may die in Purple; a build that survives Purple pressure may die in Red.

Phase-by-phase strategy

Normal (0–6 min)

The Normal phase is the calmest post-boss window. The recommended picks are Lifesteal, Defense, and Health. Lifesteal provides sustain; Defense adds flat damage reduction; Health raises the HP cap. Players who survived the Wave 8 boss can usually survive Normal without rebalancing.

Purple (~6 min, 1.6× pressure)

The Purple phase escalates the boss burst damage by 1.6×. The recommended picks are Lifesteal, Defense, and Movement Speed. Movement Speed becomes mandatory in Purple because the swarm density rises and a stationary player will be surrounded. Players who banked Damage ranks but no Speed ranks will die in Purple even if they have Max Health ranks.

Red (~12 min, 2.4× pressure)

The Red phase escalates the boss burst damage by 2.4×. The recommended picks are Lifesteal, Movement Speed, and Pierce. Pierce helps the build maintain DPS without compounding Damage ranks; Lifesteal provides sustain through the doubled burst. Tank Sustainer (Max Health + Defense + Speed + AoE coverage) is the only viable build for the Red phase — Holy Trinity builds will be one-shot.

Why Holy Trinity builds die in the Red phase

Holy Trinity builds have invested every Key and every level-up pick into DPS. The Red phase multiplies boss burst damage by 2.4×, so a build with no Max Health ranks, no Defense ranks, and no Movement Speed ranks will be one-shot. The Wave Survival DPS calculator flags this as the hits-to-death < 1 branch and labels it “one-shot territory” — the calculator has crossed outside its calibrated range.

How to plan for the Red phase

If you intend to push into the Red phase:

1. Bank Max Health and Defense ranks first. The Red phase multiplies burst damage by 2.4×, so the durability multipliers are the load-bearing investment.
2. Bank Player Speed ranks. Movement Speed becomes mandatory in Purple and stays mandatory in Red.
3. Keep one DPS card rotation available. Pierce is the recommended Red-phase pick because it lets you maintain DPS without committing to more Damage ranks.
4. Avoid the Holy Trinity. The Holy Trinity compounds multiplicatively on DPS but does nothing for durability. Red-phase runs require durability first, DPS second.

How the calculator surfaces ghost-phase pressure

The Wave Survival DPS calculator accepts an elapsed_minutes input and toggles the ghost-phase multiplier:

• elapsed_min < 6: 1.0×
• elapsed_min < 12: 1.6×
• else: 2.4×

The multiplier scales the boss burst damage and the mob damage-per-hit. Set elapsed_min to 0 for the Wave 8 boss check; set it to 8 to model the Purple phase; set it to 14 to model the Red phase. The calculator’s hits-to-death branch will flag one-shot territory at the Red phase for glass-cannon builds.

Sources and verification

The ghost-phase detail is sourced from the community guides (NerdsChalk and Roonby) and treated as a community-corroborated claim. The pressure multipliers are calibrated against the optimizer spec. All claims on this page were last verified on 2026-08-01.