When Thousand Tail Watcher reduces a unit's might by 3, and that unit is then recalled by Sett (The Boss) legend effect, does the might reduction persist or reset?

Ruling: The might reduction from Thousand Tail Watcher persists on the unit even after it is recalled by Sett (The Boss) effect. The reduction lasts until end of turn.

Nuances:

• The unit never technically left the field (it was exhausted and recalled, not removed), so temporary effects continue to apply
• If a unit would have negative might from an effect like Smokescreen and is recalled, it does not die - it returns with its base might minus the reduction and 0 damage