unit-sei

Sei is a Tier 4 naval combat unit that functions as a heavy surface warship in Mindustry. Introduced in Version 6.0, it serves as a frontline damage dealer for water-based assaults and defensive control of deep-water lanes. The unit mounts a combination of missile and ballistic weapons that let it lay down sustained, high‑area damage and punch through enemy lines; its large health pool and mobility make it a keystone of naval "death ball" compositions when paired with support ships.

The Sei’s armament is built around two primary weapon groups. The launcher battery fires fast, homing missile barrages: the salvo pattern consists of 6 shots per round at an effective rate of 8 projectiles per second (1.33 rounds/sec), with moderate inaccuracy (about 7°), dealing 42 damage per missile and producing significant area damage (45 area damage reaching roughly 4.3 tiles). Complementing the missile barrage are heavy ballistic mounts that shoot armor‑piercing style bullets (described in older text as armor‑piercing, though the mounted weapons themselves lack formal armor penetration): these fire in two banks with a slower cadence (3 shots per round split across two mounts, effectively 2×1.5/sec—0.5 rounds/sec per bank), much tighter accuracy (1°) and higher per‑shot damage (57). The missile arm provides wide, homing area denial while the ballistics supply concentrated single‑target damage.

In play, Sei excels at both offense and area denial. When produced alongside support naval units such as Oxynoe (damage boosting) and Cyerce (healing), the Sei can form a near‑unstoppable formation that steamrolls enemy sectors and cores accessible by water. On defense, its sheer firepower can substitute for static turrets in holding large water expanses. Its mobility allows it to flank or converge on vulnerable enemy cores and structures, and its durability has been buffed in several builds (health increases noted across updates).

Several practical notes and interactions:

• Sei is especially dangerous to stationary targets and enemy cores due to high area damage; kill it quickly before multiple projectiles connect to avoid catastrophic core damage.
• As a naval unit, Sei is immune to Wet status effects; some combinations that rely on Wet (for added damage or status) will be less effective—reports suggest Surge Alloy + Tsunami approaches are weaker versus Sei than Blast Compound + Pooled Cryofluid setups.
• In open water maps where ships can approach from many vectors (for example, Naval Fortress), more mobile or high‑burst naval units like Foreshadow can sometimes get effective damage in before a Sei fully retaliates.
• Although described as firing “armor‑piercing bullets” in older descriptions, none of its weapons currently grant armor penetration; this appears to be anachronistic text rather than a functional trait.
• Historic balance changes include increases to health, tweaks to range, a speed normalization (speed converted to tiles/sec), a small decrease in item capacity, and removal of a command limit—indicating continued tuning of its durability and strategic value.

Sei is named after the sei whale (Balaenoptera borealis). Graphically, some of its mounted swarmer elements recall earlier swarmer sprites with altered coloring.