Walkthrough tips, Discussion of Campaigns [Heroes 5]

Damn! I'm on the last mission for the Dark Elves. It's relatively easy up to a certain point. Imagine, after defeating legions, just legions of demons, I reached the "edge of the empire," and it turns out I need to bring both heroes there! And at the beginning of the map, they specifically placed a Sanctuary, like, "put your hero with 1 Lizardman here, and you go wherever you want with a normal army." So, here's the thing. I barely left the Sanctuary when a demon with a legion of Cerberuses rushed at me. I have an expert in logistics and stables – I pulled away. Just as I'm about to go through the gate, another demon hero arrives with 43 Archdevils, 500 Cerberuses, 50 Pit Lords, 135 Succubus Mistresses, 600+ Horned Demons, and a legion of Imps. I have 15 Black Dragons, 350 Griffins, 45 Hydras, 80 Minotaurs, and 34 Twilight Vampiresses. THAT'S IT! The enemy is level 30, and I don't even know how or what to use to defeat him – 43 Archdevils tear through everything immediately, plus the gate... Oh my god... In short, do I really have to go through legions of enemies again (in total, I've defeated several dozen stacks of enemies, from Imps to Cerberuses and Succubi, each with about 500 units)... What the hell... What will happen next? =) By the way, it's difficult! I like it!