it's basically shadow of ronin events only different: ronin's a dragonfolk (lightning) who because the world was pretty shit to him, grew bitter and willing to get back at it for everything and picks up a bit of a role of getting items that otherwise isn't safe for regular people to handle. doesn't handle the obsidian glaive + kidnapping of zane + pixal (that's someone else at play), but he's still finding the elemental forges & primal fulcrum. he already found the lightning forge while looking at an area and is very fucked up by exposure to it so at this point it's an urge he cannot control

by the end of game events, ronin gets trapped in the ethereal divide because he's too far out of range to call for r.e.x. + he rejects help from the ninja so he's stuck there for months (albeit with his spouse, archer who pops up as a ghost looking for him at some point) until morro uses the armor to try and get one of the weapon masters (grabs archer instead by complete accident because he's a ghost and also in the way) and hours later, after morro's left, ronin suddenly pops up in the museum.

misako gets a message about a "tar monster" in the museum from a coworker who thinks she'd do a much better job handling it and, after calming down the giant dragon-adjacent thing with multiple eyes, finds out that it's ronin! oops! it's scared and confused and remembers NOTHING!

tau basically looks like the drawing usually and constantly drips a tar-like substance, but when they get upset their form just destabilizes into various monster-esque forms (one being dragon-esque). a lot of how they function also no longer makes sense! they can't talk anymore because their ability to do so is just mostly melted. they can make weird sounds though and still knows sign language (whatever ninjago sign language would look like) they're basically irradiated! ever

also extra bonus: because it was careless with handling ancient artifacts (not actually making sure they weren't cursed, using elemental artifacts despite the fact they shouldn't), when it used the elemental forges they ALSO kinda fucked it up before the ethereal divide did! it's elementally charged but can't actually... use it like it did during the final fight.

they mostly got a few weird things going on that could be attributed to the four elements. dragon-adjacent form does however have the ability to breathe elements albeit only doing it out of instinct + with little control over it.