Generally, Vesper is not an outgoing or charismatic person, only doing things if it is necessary for them to do so. Considering their childhood, they are fairly cautious of who they decide to trust. Even though it has been a long time, they are not 100% sure the facility has given up on them

As an artificial human, Vesper has peak physical form, with unnaturally high intelligence and awareness.

Part of a project to create the ultimate human, Vesper was born into a lab, tested on and modified to create the ultimate human, they were raised by the scientist that created them and grew up under their care. It was when the other scientists in the lab noticed them growing far too attached to their creation, they decided to decommission the project and discard the creation. In an outburst, the scientist gave the young Vesper their coat and told them to run as far as their legs would take them, and never turn back.