Trulon: The Shadow Engine (EP)
16 Achievements
Unscathed
Win a battle without taking any damage
55.7%
How to unlock the Unscathed achievement in Trulon: The Shadow Engine - Definitive Guide
After talking to the Mayor and having to go do your first quest your first battle will be against a monkey. If you just use the wildcard Protective Stance which should be the only wildcard you have (the card that is right next to your normal attack on the far right) you won't take any damage due to the +50% defence and with each turn you will continue to get the same card. It should only take two or three turns before defeating the enemy. Once you beat them both the achievement for only using wildcards and taking no damage will unlock.
This is actually easiest done in the first battle of the game where you can use wildcards. You will only have one wildcard available (Protective Stance) and using this you should not take any damage from attacks, unless the enemy uses an attack that boosts its damage. Continue to use ONLY the wildcard each turn and you'll eventually kill the enemies and avoid all damage. If they use a damage boosting card, it only takes about two minutes to get to this point in the story, so just start a new game.
Another great spot to get this is against the shadow fox enemies in the Undercity. They always use two buff cards on their first two turns, and they can be stunned. Equip Roth with two stun cards and this essentially gives you four full turns before they will attack you. Use Haste and any damage boosting attacks with Gladia, and Invigorate her to easily kill them without getting hit.