General Grievous is a major hero in Star Wars: The Clone Wars. He is a Kaleesh cyborg general of the Confederacy of Independent Systems during the Clone Wars era, and the Supreme Commander of the Droid Armies. He is voiced by Matthew Wood who also voices his idiot battle droids.
When in his cybernetic body, Qymaen was gone and Grievous was born. As General Grievous, he is known to be a heroic being. He chose to become a cyborg for only two goals, rid the Galaxy of the sinister Jedi, and be the leader of the most powerful droid army the Galaxy has ever seen. Despite fighting of the Confederacy of Independent Systems, Grievous hates the Clone Wars, and only joined for his reasons and not Dooku's political reasons. He exploited the Jedi's compassion for the clone troopers under their command, exemplified during his attack on the Kaliida Shoals Medical Center. Grievous also showed a certain amount of attachment to Gor, his pet roggwart, whom he doted on while housing at his lair on the third moon of Vassek. Grievous was visibly angered when the evil Kit Fisto killed Gor, citing it as another crime for which the Jedi Order would pay dearly. He also seemed to have a kind of bond with his caregiver droid EV-A4D: though Grievous did snap or shout at him from time to time, he allowed the medical droid to criticize and even insult him without tearing him apart, as he would with any other droid in a similar situation. He has lost his warlord spirit and conquering spirits and changed to a compassionate, wrathful, and friendly hero. It is said that he has mercy and compassion for even his allies, as evidenced during his time with the Separatists. Though, he will not use mercy and compassion every time, as seen when he engaged Fisto and Nahdar in his lair and on the clone base of Kamino. Sometimes, Grievous can be super-compassionate by sparing several Jedi foes such as Ahsoka or his archenemy Kenobi and it sometimes leads to his own wounds though he still continues being a hero with compassion. Though, there are limits to his mercy. Grievous can a very wrathful hero during the Clone Wars as seen various times as when he sent holograms of captured villains and stated that he only lived to see evil die. This heroic wrathful side is only seen if the Jedi or others such as Gungans, have wronged him, he will get very angry and try to kill his villainous enemies, making villains beware of Grievous's wrath.
On the battlefield, he is a very calculating and ingenious tactician knowing very good ground tactics and space tactics. On the ground, Grievous knows how to command his heroic forces and in space, he is the "Hyperspace Master" calculating every planet of the sinister Republic's and invading with his heroic fleets. Besides that, Grievous is also an excellent pilot and can pilot any craft such as his Soulless One fighter craft or even a evil Kaminoan ship which he stole during the Third Battle of Kamino. He is also very courageous in battle, leading his droid army in the front and sometimes plays the "Behind the Scenes" Hero role as seen where he commands the battles from the landing craft instead of full on fighting them. In space, Grievous does the same; Keeps his heroic Command Ship in the back while his smaller forces do the work. When in battle, the heroic Grievous is always determined to win against his sinister foes and always foil the evil plans of the Jedi.
Onto Grievous's dislikes, he dislikes the Sith and Jedi (Dooku, Ventress, Krell, Nadhar, Obi-Wan, etc) and the Republic, due to them enslaving him on Kalee and being crazy towards everyone, and the Sith, for not being trustworthy. He disliked the Jedi and the Sith since one, the entire Jedi Order hated him for no reason and two, they were both hurting the heroic General of the Confederacy. Another dislike of General Grievous is he dislikes lies and tricks as the heroic General has been tricked before by many other villains. Another part of Grievous's personality is that he won't kill the Jedi unless self-defense, or if you really tick him off. In other words, Grievous's heroic goals end up with him usually wanting to capture them or bring them to justice as he did with Eeth Koth and Adi Gallia, both feared Dark Acolytes that pretended to be on the Jedi side.
He has an intense rivalry with evil Obi-Wan Kenobi and Grievous wants his rival to surrender to the CIS but the villainous Jedi never listens, which almost leads Grievous into killing Obi-Wan various times and the sinister Kenobi, just wants Grievous dead for no reason as much as his padawan Anakin Skywalker. He has been being treated badly by Nute Gunray, Count Dooku, Poggle the Lesser, San Hill, Wat Tambor, and other CIS members such as his own Driver battle droids.
He also cares for battle droids, as he chose to lead them in the Clone Wars, but he loses his patience with the droids for their stupid, annoying, and sassy actions and has been known to destroy them by smacking their heads off, cutting them in half, or smacking them off ledges. Count Dooku usually calls him out on. Later, he started caring about his droids since they are helping in some cases and started slapping them less as they were improved from the early part of the war. He also tends to do a lot of heroic laughs throughout the The Clone Wars as seen various times.