Quasar

With a need to create links between the distant cosmos and Earth in time for the Avengers: Infinity War movies, one way of doing that could be to introduce Wendell Vaughn AKA Quasar.

Vaughn was a failed field operative in S.H.I.E.L.D. because he lacked the killer instinct required to work for them. However, as a researcher for the organisation he found himself collecting data from scientists studying the Quantum Bands when the facility he was in was attacked by A.I.M. and became a hero in his own right on that day. After already having witnessed a test pilot die trying too hard to use the Quantum Bands, Vaughn opted to put them on anyway in an attempt to fend off A.I.M. It worked, as he decided to just "go with the flow". His lack of conviction, which had previously proved his undoing, worked for him in this case. He became Quasar "“ a cosmic hero and protector of the universe.

That responsibility translates perfectly into an appearance in the Infinity War movies – as it did in the Infinity Gauntlet comic book arc – with Vaughn defending the universe against its potential destruction at the hands of Thanos. He’d be a much-needed ally to the heroes of the MCU.