Apparently, a decade on, the game can sometimes crash on newer versions of Windows and Steam Deck. If this happens during a cutscene you were intended to re-recruit a character on in NewGame+/Play+. there's a rare chance a character might not rejoin. Luckily, it's an easy fix!

1. Close the game.
2. Right click Defender's Quest in your Steam library and temporarily turn off Cloud Saves so they don't interfere.
3. Go to C:\Users\[USERNAME]\AppData\Roaming\LevelUpLabs\DefendersQuest
4. Create a copy of your save file somewhere, just in case!
5. Right click your save file and select Open With -> Notepad.
6. CTRL+F classes_hidden to get to the right spot.
7. Delete the relevant line of the missing unit above <\plus_classes_hidden>

If you're, for example, missing the Dragon Niru you would delete <_class id="dragon"/>

8. Save the file, load the game up, problem should be solved.

If, on the other hand, you're not in NG+/Play+... things are a little more difficult.

If you're missing Markos the Knight as most people seem to be, look for a section like instead. If you're missing Markos, what you want to do is to find the spot below Ice Mages and paste this in:


And if you're missing a spell, follow these instructions replacing step 6 onwards from above:

Near the top you'll see Azra and her list of spells. It should look something like this:


Look through your list of spells and see what's missing from the above list. Copy the missing line, paste where it's supposed to go in that list.