Huge news for Agents of SHIELD fans. Not only is a third season of the action-adventure series pretty much guaranteed, but Marvel is quietly developing a spinoff for ABC.

We’re told a spinoff is being developed by SHIELD executive producer Jeffrey Bell (Angel, The X-Files) and SHIELD writer Paul Zbyszewski (Lost, Hawaii Five-0).

We don’t know is which characters from the current series will be moving over to the proposed spinoff — so let the speculation being on that. There won’t be an implanted pilot episode this season directly setting up the spinoff, either (like how CW launched The Flash out of Arrow). However, story elements that are still to come on SHIELD this year will be used to lay the groundwork for the potential new series. So by the end of the season — assuming the details for this project haven’t already leaked, which is rather unlikely — the spinoff concept should be clear.

Under the best-case scenario, the spinoff would hit ABC as soon as this fall. But there are other timing possibilities too, including midseason. Of course, the spinoff also might not even happen. Not only is SHIELD not yet officially renewed, but ABC has yet to select which of its crop of pilots will receive series orders — decisions that could impact the SHIELD spinoff plan.

SHIELD currently averages 7.4 million viewers and a 2.8 rating among adults 18-49, when including seven days of DVR playback. If greenlit, the spinoff would expand Marvel’s TV empire yet again. On ABC there’s SHIELD and Agent Carter (that latter, we’re told, has about a roughly 60 percent chance of returning for a second season). Plus the studio has its multi-title Netflix slate in the pipeline which launches tomorrow with Daredevil. ABC does not comment on current development, and Marvel had no comment.

So which character(s) do you think Marvel is eyeing for the SHIELD spinoff?

Other Marvel news this morning: Daredevil: New trailers reveal red suit and how a blind hero learned to fight