Is it possible to identify mercenaries in realm battles?

In Chaos Reborn it's possible to recruit mercenaries from towns or scripted events. These units will remain in your company after battles if they are not killed. You can also recruit settlements, which provide fighters who can be directed to nearby battles. These units persist after the battle, but are less precious than mercenaries because of their limited range and because they regenerate over time. Finally, wizards cast creature spells which do not persist after battles.

As a result, I prefer to keep mercenaries close to my wizard as guards and avoid sending them to parts of the map where they are more likely to be killed. Given the choice, I also prefer to use creatures I cast in battle as my vanguard. With a bit of effort, I can remember the creatures I cast from one turn to the next. But if I have mercenaries and settlement fighters of the same unit type, I have not discovered a way to differentiate which units I want to preserve.

Is this information missing in the interface or have I not looked in the right place?

This isn't possible in the interface, you can use the replay button to play back the game from any point to easily work it out though.

Also worth equipping a raise dead, if a merc is killed and you raise it then keep the undead version alive they will persist to future battles (although they lose the undead status between battles and return to normal)