AoS headcanon that doesn't matter
So what if at one point pre - Infinity War Fitzsimmoms ends up meeting Romanoff and Barton. I can just imagine Romanoff and Barton giving Culson a look like /really, these two?/ but then when HYDRA ends up taking over whatever SHIELD base they're in the HYDRA agents detain Culson, Romanoff and Barton cause they think their the main threat, but then Fitzsimmons ends up using their badassery to take back the SHIELD base and once Romanoff and Barton are finally released from their cuffs Culson looks at Fitzsimmons with pride then turns to Romanoff and Barton with a look that just says /don't you ever underestimate by bus children again/.
And that's it. That's how the Avengers are finally introduced into AoS.
Please don't steal or repost without asking first.
