The Brightshore campaign and associated online “off-shoot” campaigns used a system for character creation and advancement that is nearly identical to that used by Aethervane. As such, any player character that would currently be playable in the Brightshore campaign can be transferred to the Aethervane campaign, using the following rules.
Any character that followed the standard Brightshore rules in terms of character creation and advancement is eligible to be imported into Aethervane. In other words, if your character is from the main Brightshore campaign or was approved to transfer into the Brightshore campaign from one of the online “off-shoot” campaigns that occurred during the pandemic hiatus, your character is eligible.
Your character will start in Bleak Haven. How exactly your character arrives there is up to you to work out with the Gamekeepers, but the easiest answer is that a planar event related to the Fog, such as an Ether Cyclone (see the Dungeon Master's Guide, page 49), hurled your character into the Astral Plane.
You will not be able to return to Lorica. In the Aethervane universe, Lorica has mysteriously vanished. The planet Rythea remains, however, along with the lands that were developed during the pandemic hiatus (such as Hon'ni, Karmell, and Prokopia).
You keep all of the character's current experience. You keep your current class levels, feats, subclasses, and background.
You may take a one time hit to total XP to knock yourself down in level as far as you want. You would naturally lose any skills, traits, spells, etc. that came with that higher level. Thereafter, progression would be as normal.
Due to importing your existing character, which has XP and backstory, you are unable to make changes to your character between their initial and subsequent adventures in Aethervane.
(This is an exception to the normal level 1 “you may rewrite your characters between sessions 1 and 2” rule, which would normally let you change things such as skills, backgrounds, or similar.)
That being said, technically the Common language that was spoken in the Brightshore campaign (Prokopian Common) is not the same Common as in Aethervane (Planar Common). You may exchange one of your character's languages for (Planar) Common.
All of your character's current money and equipment is lost, except for 1 non-magical weapon, 1 non-magical armor, and 1 miscellaneous non-magical item of your choice. You may not keep any magic items (including attuned, unattuned, permanent, consumable, or cursed items).
In addition to the chosen weapon, armor, and miscellaneous item, you may start with the standard equipment and gold for your class and background.
You may not keep any special boons your character received.
You may not keep any retainers, hirelings, familiars, pets, etc. Of course, if you have the spell find familiar or similar, you could cast that once you have the prerequisites in Bleak Haven and obtain a familiar per normal.