Warcraft 3 DL Hero Siege Evil Spawn 3.6 solo Illidan on easy

Map - www.epicwar.co...
This is much easier with 2-3 players, but can be done solo with Illidan if you use your zeppelin's ability to attack with an orb. Illidan is required regardless of the number of players because the final boss has divine armor, and Illidan's second metamorphosis has chaos damage. His range is also crucial when dealing with the 3 bosses without opening the gate (near 44:00 mark). If the gate is open, Arthas becomes nearly impossible to deal with. He simply hits too hard.
Malygos is much faster at killing the 3 bosses behind the gate with his death and decay ability - he can kill all 3 with a single cast, but he is practically useless against the final boss. If there are 2 or more players, having Malygos and Illidan is the best choice. If attempting solo, Illidan is your only option as far as I know.