Furnace is a ruthless and remorseless killer. He is extremely deadly and enjoys hunting down his enemies. Furnace is very obedient towards his master Dr. Robotnik and loyal Furnace addresses his master as "Lord Robotnik" as a sign of respect and is willing to do whatever his master wants him to do. Furnace is very cunning and intelligent as shown when he pretends to malfunction in an attempt to kill Sonic, Furnace shows how ruthless he is when Sonic dodges the attack and then Furnace immediately attacks Sonic and chases him. Furnace even threatens Sonic after and promises Sonic that he will cook him alive and feed him to his master Robotnik. Furnace is very cruel and mischievous, unlike his original counterpart (Metal Sonic) Furnace is willing to exploit all weaknesses of his opponents as Furnace was able to exploit Sonic's cockiness and ego which is what allowed him to kill Sonic in the bad non-canon ending in the first place. Furnace has a deep hatred for Sonic as shown when he threatens Sonic the moment he encounters them and threatens to skewer and cook them alive. Furnace seems to hate anyone who dislikes his master or shows him any sign or disrespect.