Operation X: plan the roster
This is an exploration/progression activity with limited use of individual heroes inside a run. Preserve your reliable boss killer instead of spending its available fights on every easy encounter. Use secondary heroes and obtainable buffs to cover the route. [S22]
Practical clear strategy
Inspect the map and remaining encounters, collect useful buffs and treasure, and bring area damage for groups. Before the final boss, check that your intended hero still has the resources to fight. A high recommended BP does not account for every buff you collected; survival alone can still lose to the timer. [S22]
When to pause progression
If the final battle consistently times out, improve gear, cards and the relevant rotation. If you cannot finish the route because the strongest hero was exhausted, change your allocation on the next run. These are different problems and need different fixes.
Hero Theater, Mock Trial and seasonal events
These modes can use special buffs, loaned heroes or event-only rules. Read the mode description before importing the normal build. A Stain enhanced-E build in Mock Trial, for example, is not evidence for the same duration or damage outside that event. [S32]
General event method
Identify whether scoring favors clear time, survival, hits, one target or waves. Choose buffs that multiply the skill you repeatedly use. Keep a defensive option if it turns failed runs into consistent clears. Re-test after the event changes the kit or gives a new enhancement.
Coverage boundary
Exact map solutions, seasonal stage lists and preservation-server additions were not recoverable from the referenced research. This page gives a usable approach without inventing current stages, puzzle answers or guaranteed rewards.