Saving troop state after loose / escape battle.

I want achieve something like this on example:

Party faces troops with 3 units and they are able to kill at least one, but player decides to escape battle, troop squad now has now
2 units. But by default, when player decides to re-engage battle troops are reseting to full HP and full defined squad in database.

I want to save that state when (e.g) troop count 2 units, and some eventual damage dealed to troops. To be more precise:
I encounter squad of 3 bosses with let's say... 10k HP, party kills 1 boss, and of those bosses remains with 9k HP, party retreats and reencounter them, so they should be 2 bosses and of them has 9k HP. Is this possible to do that?

If it's just HP values, all you need are variables to keep track of monster HP, and then remove the values from monster HP when re-entering battle.
It becomes more complicated if you allow to enter other encounters inbetween returning to a saved encounter, allow for multiple saved encounters, or wish to also save states and turn counts remaining per state. In that case, a plugin would be more suitable.

Nope, not just HP, but:
- HP
- MP
- Number of remaining troops in squad

You can do it with Variables
Create a variable and store Troop's Hp in that
Create a variable and store Troop's Mp in that
Create troop with 1 Enemy
Create troop with 2 Enemy
Create troop with 3 Enemy
Turn switch on when any troop die
Create conditional branches on which troop to encounter
You have got it