I'm thinking the fight should begin at the gate. Minthara holds back and lets her minions throw themselves at it. It seems like the heroes are winning. Maybe only 5 of Minthara's troops are standing...
Minthara smiles and calls in the second wave. Twenty more troops show up. Some are going through the secret tunnels, but most charging the gate. An ogre throws an explosive barrel at the gate, blowing it open if it isn't yet. More sword spiders arrive.
You have a choice. Keep fighting to hold the gate or fall back to where the rest of the Druid and Tiefling forces are, near Arron's merchant stand. They've set up a barricade there. Several druids are sent to defend the secret tunnels.
But if you didn't expose Kagha, no druids help you. 😈 Enemies come from behind after several rounds, coming in from the secret tunnels. Now the grove is being overrun. Some enemies are trying to get at the kids. What will you do?
If Batman can have Robin - who is basically a child wearing bright red and yellow - as a bullet sponge, then I can use tiefling children for the same.