No need to panic. Options: 1. The simplest and most basic approach is hit and run. Attack the skeletons with magic and retreat. In other words, maximize their weakness – their low hit points! A few such attacks, and they'll be sent back to the graveyard. 2. Galthran rarely uses water magic. The problem isn't that it's not given to him, but that he doesn't take it:))). Therefore, teleportation is unlikely. By the way, in general, Galthran without teleportation isn't very well-suited for storming castles. 3. Traditionally, barbarian troops and the archers of the Tower are good against hordes of skeletons – this is described above. 4. Unattended units, primarily hydras, as well as cerberuses, are also suitable for reducing the number of skeletons. 5. If the game has dragged on for too long, it might be worth considering whether to drag it on even more. Using hit and run and accumulating the level 7 bonus (which isn't the strongest for the undead) can then allow you to turn the tide in your favor. 6. Galthran has two weaknesses. By the middle of the game, only one remains, but it's very noticeable. He's slow!!! You need to try to exploit this. 7. There are no invincible heroes!