Hi, if you're trying to get over chapter 8 you might ecounter some difficulties when reaching 8-10. when the clock hits 55 sec left reeinforcements arrive and distroy all or almost all your troops in 1 sec so you obviously want to pass each stage before the clock hits 55 secs.
for that purpose I decided to use Big Guy, Trickster, Petit Devil, Tracker and prima Donna (this last one because lets face it you still need a healer)
https://youtu.be/0Ks-O_0xJRg (video here)
some important instructions during the fight might also help,
1 try to save special effects for the next stage
2 specifically for 8-12, in the second stage you want to kill deamon first otherwise he'll distroy petit devil and prima donna
3 in chapter 8-12 go hard on darck knight, when he's down make sure not to waste any special skills (stop auto play) once he's up hit him with auto play or everything you have