Why is Illidan a bad guy?
Born a night elf and sorcerer, his pursuit of power led him to commit several horrific acts against his own people, which earned him the nickname "the Betrayer" and to become the first Demon Hunter.Illidan Stormrage is a major false antagonist, and later main protagonist of the Warcraft universe, being the main protagonist of the Legion expansion and the series as a whole.Originally a powerful night elf sorcerer, Illidan officially betrayed his people by defecting to the demonic Burning Legion during the War of the Ancients, though his reasons for doing so were noble as he secretly aimed to repel the Legion's invasion.

How did Illidan become a demon : Arthas manipulated Illidan into seeking out a powerful artifact, the skull of the Orc warlock Gul'dan, claiming that if it was destroyed Felwood's corruption would end. Believing it his last chance for redemption, Illidan destroyed the skull and absorbed its power transforming into the demon seen in Burning Crusade.

Why was Arthas stronger than Illidan

Arthas uses heavy armor and relies on effective blows with his Runeblade, which is quite a sentient blade. Illidan runs around half naked, uses the Blades of Azzinoth which are magical but not as strong as Frostmourne in my opinion. Arthas draws power from Northrend and the Lich King, the closer he is, the better.

What did Illidan do for 10,000 years : The main reason he was imprisoned for 10,000 years was he remade the well of eternity.

No he's not. He was never “evil”. He just has a strong hatred for the burning legion and their leaders. He was portraited as an antagonist in TBC but that was ages ago, his character arc since the legion expansion has changed drastically.

Sargeras

If anything can be referred to as 'true evil', it is Sargeras. The Dark Titan is the creator of the Burning Legion who attacked Azeroth and almost destroyed it completely. Sargeras' sole goal is to destroy all life in the Universe and undo what his kin had worked so hard to achieve.

Who is Illidan in love with

Tyrande

But, even after such abandonment, Illidan's love for Tyrande did not lessen. In a confrontation on the Broken Isles, Malfurion and Tyrande's forces faced Illidan's. Illidan and his retainers were forced to flee, but were followed by Tyrande.The Burning Crusade

He fashioned himself into an oppressive dictator and became extremely unpopular to peaceful inhabitants of Outland.Arthas' power is diminished due to Illidan using the Eye of Sargeras to crack the Frozen Throne, and so the Lich King is losing power. Even still, prior to becoming the Lich King fully, and weakened, Arthas still defeats Illidan in the duel.

Sargaras

In the World of Warcraft mythology, who is the strongest The strongest known being would likely be Sargaras. Sargaras killed the rest of the Titan pantheon by himself.

Who is the ultimate evil in WoW : Sargeras is one of the main antagonists of the Warcraft franchise.

Who is the unnamed villain : The Unnamed Villain, also referred to as Mysterious Villain, is a figure cloaked in shadow who is the founder of the Brain Factory, creator of the Brains and the one who received the blueprints of the Hero Factory from Black Phantom after the mass Breakout.

How old is Illidan

According to the Warcraft III: Reign of Chaos manual, Malfurion and Illidan Stormrage were 15,032 years old, and Tyrande Whisperwind was 13,836 years old, at the time of the Third War.

Arthas Menethil is a major antagonist of the Warcraft franchise.Sargeras

If anything can be referred to as 'true evil', it is Sargeras. The Dark Titan is the creator of the Burning Legion who attacked Azeroth and almost destroyed it completely. Sargeras' sole goal is to destroy all life in the Universe and undo what his kin had worked so hard to achieve.

Who is the bad guy in Warcraft : Sargeras is one of the main antagonists of the Warcraft franchise. He is the creator and leader of the Burning Legion, a former member of the Pantheon, and a mighty bronze titan until he was corrupted beyond redemption and became the Titans' worst enemy.