Sei

Sei is a Tier 4 naval unit that functions as a heavy-water battleship, delivering immense burst DPS by combining missile salvos with high-damage, armor-piercing-styled bullets. It appears in aquatic maps and naval-focused sectors where its long range and powerful weapons allow it to dominate open water, threaten enemy Cores from afar, and replace static turrets as a mobile sea-based artillery platform.

The unit mounts two distinct weapon systems that fire in coordinated volleys. One weapon launches a barrage of homing missiles: it fires 6 shots per volley with an effective firing rhythm of 1.33 volleys per second (8 projectiles per second total), 42 damage per missile, 45 area damage affecting roughly 4.3 tiles, and a wide inaccuracy cone of 7 degrees; the homing property lets these missiles track targets. The second weapon is a rapid heavy-bullet mount that fires armor-piercing-style projectiles (note: the projectiles do not actually have armor penetration mechanics) in grouped volleys: it effectively produces two staggered bursts (3 shots per round at a combined cadence of 2 × 1.5 shots/sec resulting in two 0.5 rounds/sec streams), with tight 1 degree inaccuracy and 57 damage per hit. Together these weapons produce extremely high concentrated damage capable of shredding most units and structures.

Sei has large health and long range compared to earlier units, and its mobility is tuned for naval engagement (speed was standardized to tile/sec in later builds). Over development it received several balance changes: health was increased across multiple builds (eventually to 11000 in one update), range has been adjusted (notably between 32 and 35 blocks), item capacity was slightly reduced (from 160 to 150), and its earlier command limit was removed. The unit was introduced in Version 6.0.

Use Sei as the core of a naval deathball: produce multiple Seis and support naval units that boost damage and survivability to create an almost unstoppable formation that can steamroll enemy defenses and Cores. Oxynoe and Cyerce provide damage boosting and healing to extend the Sei’s frontline pressure; Aegires offers healing and defense but at higher cost. In defensive roles, a single Sei or a small group can control deep water lanes and deter amphibious assaults where you would otherwise need many turrets.

Counterplay centers on eliminating Seis before their projectiles connect to critical structures. They are vulnerable to concentrated focus fire from dedicated long-range unit killers; even strong anti-unit ships such as Arkyd can be overwhelmed if they are not prioritized fast enough. Because Sei is a naval unit it is immune to Wet status, so combos that rely on Wet-generated damage reductions or interactions (for example, using Surge Alloy ammo plus Shallow Water in a Tsunami) are less effective. Instead, damage types that ignore or exploit other debuffs—such as Blast Compound or Pooled Cryofluid-augmented munitions—perform better. Fast, high-damage flankers like Foreshadow can also deal significant damage if they close quickly in open-water maps where maneuvering and surrounding are possible.

Additional notes: the unit’s name references the sei whale (Balaenoptera borealis). Despite flavor text referencing armor-piercing bullets, its weapons do not have armor penetration mechanics in current posted stats; this appears to be a descriptive oversight from older versions. The mounted swarmer visual is similar to earlier swarmer sprites with different coloration.