The MSN-06S Sinanju (aka Sinanju) is a mobile suit featured in the Mobile Suit Gundam Unicorn novel, its OVA adaptation and the television re-cut. A modified version of the MSN-06S Sinanju Stein, it was piloted by Full Frontal.

Originally the MSN-06S Sinanju Stein developed by Anaheim Electronics as part of the Earth Federation's "UC Project", its movable frame is partly made from Psycho-Frame materials. This mobile suit was then stolen and modified into the MSN-06S Sinanju by the Neo Zeon remnant group known as "The Sleeves", and became the personal machine of the group's leader, Full Frontal.

All of the Gundam-like features (except for the head-mounted vulcan guns) in the Sinanju Stein have been replaced with a Zeonic design and weaponry. Painted in crimson and with gold engraving, the Sinanju looks like the emblem of the Neo Zeon forces embodied. This decoration not only strengthens the armor, but is also said to be a design that is meant to control the organization known as the Neo Zeon remnants. The Sinanju Stein was an experimental machine, so there were some concerns about the armor's resistance to elasticity, but in order to increase the pilot's survival, the beam coating was strengthened from the two-layer structure used in most conventional MS to a five-layer structure, and the entire cockpit block was covered with Luna Titanium X material, and the Sinanju's armor has been strengthened as flagship machine.

The Sinanju is also equipped with thrust deflector thrusters shaped like the large wings of a bird of prey, and flexible thrusters on the left and right sides of both legs and shins. Together with the numerous thrusters located all over its body, it is capable of acrobatic maneuvering combat that is impossible for a normal MS to achieve. With its overwhelming combat ability, crimson body, and mono-eye sensor, the Sinanju reminds all who see it of the legendary "Red Comet".