Rounder

Rounder denotes a member of the shadowy mercenary team known as the Rounders, a group that operates under the cover of SERN while actually being independent from it. Rounders carry out the organization's dirtiest work, from intimidation to eliminating threats, while SERN's official research stays clean.

The team is run by a mysterious recruiter using the alias FB, who is in fact Yuugo Tennouji. FB specifically targets people who are isolated and cut off from society, such as Moeka Kiryu, and binds them psychologically by acting as the one person who truly understands them.

Despite the masks its members wear to hide their faces, the Rounders' roster shifts from timeline to timeline; known members include Nae Tennouji in one future Alpha world line, and even Rintarou Okabe himself in the Gamma Attractor Field.