Ranger - "Higher Vampire" [5th Campaign, 5th Mission]

I don't understand at all. I have 250 archers, 220 druids, and 45 dragons. And I'm being killed by 7,000 skeletons. I already have 6 Castles, what should I do?

That's not enough. I have 85 dragons and 600 archers. I don't remember how many druids. And my Daedra has 120 dragons. Daedra would have even more, but there's not enough money and resources. I also have 6 Castles, but soon I'll have 7. I recently captured the 6th. It would already be 7 if I hadn't made a big mistake.

I specifically gave the phoenixes to another hero so that he would take them to the Castle. I don't want to end the mission until I explore the entire territory and max out Faidaen. I defeated Nicholas. The shackles didn't let him escape the battlefield. After the battle, I watched a video saying that Nicholas was resurrected. This is where I made a huge mistake. I didn't notice that someone had destroyed my supply wagon. In the midst of the assault on the Castle where Vlad was holed up, when I was already ready to celebrate victory, my archers ran out of ammunition. Well, Vlad, just wait!!!

Earlier, we discussed what to do with the hordes of undead from captured Castles. IMO, replacing part of your troops with undead is not the best idea. I bought Daedra level 29 in the tavern. Now, auxiliary heroes are bringing her reinforcements from all the undead Castles. She walks near Faidaen and does auxiliary work, just in case. If Faidaen has trouble, she, or another undead hero who is just as well-leveled, will join the battle with a strong enemy. There isn't another one yet. She has the least useful specialization against undead. But it's not the worst upgrade. She has maxed out wizardry, logistics, attack, darkness, and summoning. She only lacks the phoenix spell.

Added 5 minutes ago
In the undead Castle, I found the "Astral Gate" spell. In the next campaign, Faidaen will definitely teach this spell to all his friends. I'm not sure if they'll need it. After all, Godric and Railag are brave guys. But no one has ever died from an extra spell.