I used up all my restarts and had to play as Inferno against Rampart. It went well in terms of resources (I built Ifrits in the Citadel), but I didn't get any good mages, so I switched to playing as Kel'thuzad. I reached the first treasure room on day 116, but the passage from 50-99 was blocked by Ogres. I took Pandora's Box for diamonds (it was empty because I didn't have the book) and on day 122, I went to another treasure room, and there was Solmyr with almost no army (16 Centaurs and 15 Grand Griffons). I killed Solmyr, and then he surrendered.

Thanks for the game!