Hey there, I have an idea for a battle system that might work within the game's parameters.

Remember Benton's Tournament and how you climb the ranks to reach the top? What if this system can be used for a battle instead?

For example, Wheelcum is suddenly attacked by a group of Dark Knights. This is indicated with an exclamation point on the map.  This event only happens at night time.

If you are in Wheelcum, then a prompt/speech bubble from Tristan/Hector will say a bunch of Dark Knights is attacking at the gate. Then another prompt will say if you want to join the fight. 

If you say no, then the game time will move towards morning, and a prompt on the screen that says Soldiers were able to hold off the Dark Knights from entering Wheelcum and left when Dawn came. And nothing happens with Robin Morning Wood.

If you say yes, it will show you a screen similar to the tournament, but it is a battlefield with many Dark knights in the field. You will be automatically given the position on the battlefield (at the bottom) with a battle against a Dark Knight. 

----O----

---- I ----

----O/R----

---- I ----

----X----

R - Robin

O - Enemy

/ - In battle with...

X - Defeated Enemy

If the Dark Knight defeats you in any part of the battlefield, the screen says GAME OVER, and Robin blacks out. Like all other fights, once  you are defeated, the game time moves toward morning with a prompt saying Wheelcum Soldiers were able to hold off the Dark Knights from entering Wheelcum and left when Dawn came. Also, Robin lost some stuff from inventory.

If Robin manages to defeat a Dark Knight, then Robin can progress to the next Dark Knight on the battlefield. If Robin manages to reach the top (aka Robin cutting through Dark Knights on the battlefield), the last Dark Knight in the battle would most likely be an ordinary one with a Blue Top Aura, but there is a small chance Robin will meet a Dark Knight Lieutenant. It's a Dark Knight that can change color aura like certain characters in the game.

Once Robin defeats the Dark Knight, the game time moves towards morning, and the screen prompt says Soldiers of Whelcum were able to hold off the Dark Knights from entering Wheelcum. Robin is then congratulated for fighting the leader of this assault, and (only an option) Robin is rewarded in a "special" way by Benton and Grant.

This battle template can be easily applied to any location on the map, with a prompt saying where a battle is taking place. Nothing changes if Robin goes to a different location. But if Robin chooses the battle, then another prompt will say if you want to join the fight.