History
After the remaining members of the Fantastic Four accidentally destroyed the Shi'ar throneworld when they retaliated against the Shi'ar for Reed Richards' execution, Captain America, along with the other members of the Avengers, allowed themselves to work under S.H.I.E.L.D. direction in preparation for what they assumed would be alien retaliation. However, the remaining Fantastic Four members sacrificed themselves by destroying the Skrulls' weapon, the Omni-Wave Projector, to save the other races, thus preventing the retaliation.[1]