Endoscopic Submucosal Dissection (ESD) for the removal of large lesions en-bloc is an emerging endoscopic technique with low recurrence rates. Traction assisting methods are used widely to increase exposure to the submucosal surgical field. Existing traction methods in practice suffer from inadequate strength, limiting degree of freedom and coupling motion with the endoscope. In this work, we aim to provide dexterous and independent tissue manipulation with a portable robotic traction device that is adaptable to the commercial endoscopes, as an alternative and reference to the more advanced bimanual robotic platform.