Pip tells them that they’re going to witness the grand arrival of Starfox, also known as Eros, the brother of Thanos.
The simple story is that he is an Eternal who has often to be associated with Thanos.
In fact, he was once put on trial for allegedly using his powers to coerce women into having sexual relationships with him.
But, according to Gizmodo, the MCU version of Eros might serve as a way for the universe to confront Thanos.