Ninjago: Veil of Shadows

It starts with a small coastal village - The ninja return to Stiix years after Morro because people have started vanishing again.
They assume it's ghosts at first, but it's her element, Estara's, reacting to something deeper, pulling her toward Ninjago from the Veiled Realm. Fishermen vanish overnight, leaving only wet footprints and drifting fog.
The ninja arrive to investigate. The place is silent.
Buildings half-swallowed by mist. Lanterns still burning. A table set for dinner - but no people.
Cole steps inside the fog, and his voice echoes wrong - like it's coming from underwater.
When the mist clears for a second, he sees her - a girl standing in the middle of the square, hair flowing like smoke, eyes glowing faint blue through the haze.
Before he can speak, she melts into vapor, and his vision distorts - he's suddenly back outside, heart racing.
They chase her deeper into the fog and find her fighting something - shadows moving inside the mist, attacking her like living nightmares. She fights fluidly, her blades slicing through vapor and illusion alike.
The team joins in, but every strike passes through the enemy like smoke - only Estara seems to land hits.
Afterward, when Lloyd demands answers, she just whispers, "You shouldn't have come here. The mist remembers who trespasses."