Converging threats are two visible danger fronts advancing toward the same space. Their combined loss of clearance is the rule: reveal both origins and closing direction, commit the timing before movement, and leave an ordinary route out. Two side fields close below Tavi while the upper exit remains open.

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Announce both frontsKern lights two broad side fields at the same height. Inward arrows show that their visible edges will meet below Tavi, while the upper route remains open.
Inspect converging threats A looping diagram: the boss announces two opposing side fields across a lower strip. They advance inward together, closing the center corridor, while the player walks up through an open exit. The fields then fade and the boss recovers. Boss Player

Kern lights two broad side fields at the same height. Inward arrows show that their visible edges will meet below Tavi, while the upper route remains open.

Implementation checklist

Design the two fronts, their meeting time, and a reachable full-body escape as one spatial promise.

Core checks

Three questions for the mechanic

  • Can both sources and their meeting point be read?

    Show two distinct origins, direction, footprint, and a shared arrival time. The reader should predict where the safe corridor closes without mistaking an arrow or preview line for active collision.

  • Does the union of threats leave a real exit?

    Test the player's whole body against both current fields. Measure the route to an upper or lateral exit at ordinary movement speed, including acceleration and arena boundaries; a point-sized gap is not sufficient.

  • Is the meeting and release timing fair?

    Lock the fronts before they move, make the closing rate readable, and remove both hitboxes when their visible fields fade. Reserve a useful recovery interval after the corridor is clear.

Design mistakes

  • Only one front is telegraphed

    A surprise second source changes the route after commitment. Reveal both edges before activation, or introduce the second as a separately announced escalation.

  • The apparent exit fits only a point

    A gap can look open while the player's body collides with either field. Include radius, travel time, wall clearance, and camera framing in every sampled safe route.

  • The fronts accelerate or linger invisibly

    The viewer cannot trust a closing diagram when hitboxes outrun their edges or remain after they fade. Drive motion, damage, and cleanup from the same clock.

Tuning

Tune the attack

  • Model the union, not an invented central hitbox

    Store each front's origin, width, height, timing, and current edge. A player is unsafe if either visible field overlaps their full collision body; their meeting does not add a hidden third attack.

  • Test the escape under the worst overlap

    Sample the remaining corridor width and the time needed to clear its threatened strip. Sweep each moving edge between frames so a fast front cannot cross the player unnoticed.

  • Separate convergence from crossfire

    Crossfire is about trajectories from distinct origins crossing. Here two broad fronts progressively remove the corridor even if no discrete projectiles intersect. A persistent shrinking safe zone instead constricts a region from all sides.

  • Escalate the relationship carefully

    Change one front's timing, angle, size, or the exit's location only after the base two-source pattern is learned. Keep at least one reachable route under every combination.

Arena

  • What the mechanic communicates

    Kern charges runes along two flanking walls. Their paired stone fronts close a lower passage, but Tavi can step into the open upper lane before the runes meet.

Player upgrades

  • Adapt it to the player verbs

    Basic walking must reach the exit before the fronts arrive. A jump or dash may offer an alternate crossing only when its collision and invulnerability rules explicitly support it; neither should silently become mandatory.

Do not confuse this with

  • Keep the mechanic distinct

    Convergence makes the safe corridor narrower through two announced approaching sources. Moving hazard carries one footprint across the arena, crossfire intersects discrete paths, and shrinking safe area reduces a bounded sanctuary rather than combining two fields.

Bosses that use this mechanic

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