Sanctuary – “Life in death and death in life” [Campaign 4 – Mission 4]

Is 15 cannons at the beginning nothing? Is more than 100 Shark Guards nothing? Is 20 Yuki-Onna nothing? You guys are strange...

Do you mean on the mine? That is, near the Castle?
Well, I'm playing on Easy difficulty, and I defeated all these guys with a combined squad of 37 Kappa, 5 Priestesses, and 45 Sharks (the Sharks weren't always used).

Tyangbo learned a cool spell from previous missions, I don't remember the name - it's basically "Slippery Puddle". It's a 3x3 icy surface that slows down the enemy + it damages him with icy icicles.
They lose 3 turns in this puddle while they cross it, the Kappa has time to jump, then move back and jump again + a direct attack from the hero himself. + one more "Flash" spell at the end.
They all die, and I don't lose anyone.
And with Kappa archers, it's even better) they attack in an area =)

Added 1 minute ago
Oh yes, I used the "Ice Block" spell on the Yuki so they wouldn't shoot