An ancient humanoid robot that appears in Sonic Battle. Its original name was "Gizoid", but the name Emerl was given because of its ability to absorb Chaos Emeralds.
Having been first researched upon by Gerald Robotnik, It was discovered and subsequently abandoned by Dr. Eggman. Afterwards, Emerl begins traveling alongside Sonic and each of his friends, and grows gradually smarter and stronger by imitating their abilities and absorbing Emeralds. However, gaining power over one of Eggman's weapons forces Sonic to fight Emerl himself.
A different robot called Gemerl was created from Emerl's data, following its eventual destruction.